Paladins, since The Burning Crusade can tank, though many of us still occasionally have to fight against the only views that only Warriors are tanks, and the more prevalent "Warriors are the main tank" perceptions that put Druids and Paladins on the back burner. As its been noted before on other blogs many Druids tanks would trade away their ability to DPS in order to get more tank slots, the inviability of Warrior DPS in tank gear, or Paladin healing (or DPS I suppose, but most paladins seem to heal in offspec) means that Druids are often placed to the side as they have the most viable "off-spec" role in tanking gear.

So really, in competition for the main tank slot we have Warriors and Paladins, since both of us are uncrushable, and lack a truly viable role to fill in tanking gear while not tanking. Thus this post, to see really where I see the differences and flaws of the Paladin class in tanking, and its off-spec viability. I don't want to see Paladins as the premier tanking class, but rather the 3, and soon to be 4, tanking classes all treated equally and given viable roles. In this discussion I mainly look at Warriors as our closest equivalent tanking class, both being sword and board tanks, with uncrushable status, offering us the benefits of the Druid class while maintaining the similarity to Warriors would likely be game breaking so is not considered. So looking at tanking:

On damage taken:
Paladins have slightly more base damage taken than a similarly specced Warrior, roughly 4% physical, 10% magical damage, the increased parry haste drops this warrior advantage to roughly 2.2%, so in realistic terms, not a lot in it here in terms of raw damage. Warriors however have a large number of tanking debuffs in the form of thunderclap and things like demoralising and commanding shout to decrease enemy attack speed, damage, or increase your health pool. Paladins lack utility in this role, the increased damage we take without a warrior present is very important and in many ways game breaking. Adding utility to us either through decreased damage naturally (potentially a bad route to take as a DPS Warrior or Prot Off-tank can apply their debuffs for us giving us an unfair advantage) would greatly assist in this field in making both tanks more viable in the main and off tank slots as both offer viable, stacking debuffs. The key here is that both tanking classes must be viable and offer debuffs that stack to allow either to be a suitable main tank with or without the other.

On Damage dealt:
We are tanks, threat and damage are largely unrelated for us as concepts, provided threat is high and scales well then our damage is largely irrelevant while tanking, however in the off-tank role the tanking talents and abilities should allow us (or rather Warriors if our off-role is healing) to perform with reasonable DPS, thats not to say we should compete with a rogue with Glaives, but if we reperesented 2/3rds of a retibution Paladin (~ 1800 dps on Brutallus, so giving us 1200 dps) would, while not giving us a raid spot as a DPS, make us a reasonable off-spec role to take when we can't tank a boss, yet leave us present (and really only the tanking trees should have the debuff capability to ensure multiple tanks are taken in a similar way to blessings and heroisms).

In terms of raid damage we add little to anything, offering no debuffs or buffs unless we are in a threat spec (and a retribution paladin is likely to have that ability as well without the compromises we are forced to make to take it). Warriors in contrast offer an attack power buff and Sunder Armour (their main threat tool), however this is both a blessing and a flaw, a Rogue using Improved Expose Armour will offer up a raid-wide dps increase (above that lost by themselves to apply it) at around 2000 physical damage per second, however you won't always have a rogue offering this option, where as a Warrior can always apply Sunder Armour.

On Talent trees:
The protection talent tree for Paladins is very full, with 2 typical builds 0/45+/10+ and 0/40/21, the key difference in the choices in the protection tree being Ardent Defender. The tree is very bulky with talents many talents taken for Holy Shield (required to give us the capability to remain uncrushable through fast attacks), and to give us base-line tanking abilities and threat generation. Of key concern really beyond the obvious bulk of the tree (in comparison the early Retribution tree is very well optimised for us), are Redoubt, Blessing of Sanctuary and Ardent Defender.

-- Redoubt, a proc ability to increase block, and a pre-requisite to getting our increased block value talent. As the proc is unreliable all main tank paladins are uncrushable without this triggering in single target fights, and in multiple target fights its trigger is useful, but rarely required as the charges are blown through very quickly. To make this viable in an AoE situation increasing the charges or proc rate would be beneficial, allowing it to essentially be up permanently as Holy Shield will be eaten quickly (I would prefer more charges to keep it of minimal use in boss fights). Other suggestions have been to make this a static +block% increase, this assists in allowing early gearing Paladins to reach uncrushable and additionally does not scale inversely with our gear, at current as our gear level increases so too does our avoidance, meaning fewer hits that can proc the ability making it even less reliable.

-- Blessing of Sanctuary, the 2nd of our trainable blessings in the protection tree, Kings is often taken by most other Paladins and its use it seen as almost required. Blessing of Sanctuary however is another non-scaling talent (at higher armour / avoidance the reduction this offers does not change, while block value increases in value), with little to no scaling with gear level. The non-scaling occurs because the damage is reduced before armour, so moving from a 0% reduction (upto 80 damage prevented) to a 50% armour (upto 40 damage prevented) is the same % reduction in damage offered by this, however when compared to block value appears to scale inversely, in that it is static rather than becoming more valuable. The lack of scaling occurs as no additional damage is prevented with spell damage, nor does their appear to be an increase in the damage dealt for its trigger, both of these aspects could be utilised to offset the requirements on Paladin equipment for a large range of stats allowing for a better allocation between offensive and defensive ones, and making it a viable blessing. Making this a constant reduction to physical and or magic damage would be perhaps better, making it a supremely viable AoE type talent, with reduced effectiveness on large slow hitting fights.

-- Ardent Defender, the passive shield wall, well when its not skipped. This talent really shines in instances like Mount Hyjal, where we use AoE tanking and block gear (most Paladins stacking 500-900 block for this instance). This level of block gear reduces the incoming damage per hit to the 100-3oo range meaning a very steady and reliable loss of health and ardent defender kicking in very reliably at its trigger point, the occasional spike due to group crits or Abomination knock down are handled fairly well as well as the individual damage per attack is in the 2000-3000 range. The issue of this talent (which required 40 points in protection to consider, and is generally seen as an all or nothing talent, so 45 points in protection as the default base), is that it can be skipped. On the hardest hitting bosses and trash, where we lack a response such as shield wall the ability that is designed to save us will rarely trigger, with many bosses being capable of hits of more than 7K (which would be roughly the trigger point for a 21k health Paladin). Warriors have an active ability to stop these, allowing it to be triggered only when needed, Rogues get a passive version like ours however much more powerful as it cannot be leapfrogged. To make this talent truly worthwhile simply making it non-leapfroggable would be a major step forward, letting us have a response to bad situations, even if we cannot control it.

-- Retribution tree
This tree is very nicely set for us, 10 points in this are seen as very worthwhile with often 12 or 14 spent here to increase threat or spell avoidance, not much can be said against this part of the tree as it is far less bloated for us than our own protection tree.

On Threat and scaling:
In the early end game and through the middle Paladins are the undisputed threat tanks, however T6 content changes this as our reactive damage tends to play a far reduced role (as our avoidance increases the chance of reactive damage is reduced), and the scaling of both the reactive and active damage is minimal. Our major threat source is consecration, with a 108% coefficient roughly across all ticks, this scales well with our spell damage, by contrast Holy Shield has a coefficient of around 5% ( 2.15*Base threat + 12.8% spell damage threat overall), our famous reactive damage increases by around 10 damage (19 threat) per hit between Tier 4 and Tier 6, coupled with getting hit less. Reactive damage, a key element of AoE tanking and the idea of Paladins as block tanks, is thus reduced massively over time and content level.

The discussion on reactive threat is interesting since this divides the Paladin community, while it is viable in an AoE tanking situation where the individual hits taken are very low and consistent it is relatively non-viable in boss tanking situations. The capability to use up a larger number of charges on this ability is tied to becoming closer to crushable, and increases the damage taken by the Paladin (more blocking means less raw avoidance). Again this scales inversely with gear, we cannot afford to be hit multiple times in succession without straining the healers, yet we wish to be hit for threat and mana regeneration. The solution to reactive threat and Holy Shield is a difficult one, since it fulfils the dual role of uncrushability, mitigation and threat generation. Moving Paladins into a higher reactive threat role would likely require our mitigation to be increased significantly such that we could survive a comparative time to Warriors using avoidance, however as we can wear the same gear as them instead of reactive threat gear this is potentially unbalancing again. Reactive threat must therefore be balanced, viable yet remain a low enough expected percentage of overall threat such that Paladins can tank in avoidance gear that is denied to Druids in exchange for their potential to reach the armour cap.

-- Seals and Judgements
Our seals vary greatly, generally the "on-hit" ability of our seal has a sub-25% scaling with spell damage, and the judgement something akin to the instance ~43% scaling, on a normal caster these kinds of scalings are fine as they stack a large amount of spell damage (often 2-3x that of a protection paladin), and can afford to cast longer spells that benefit from much large coefficients. As we are tanking, our spells become reduced to instant casts, otherwise we lose all of our mitigation (dodge, parry, block) while casting, making us both crushable and taking extra damage. In general these scalings should be increased (ideally the on-hit to reduce the burst nature of Paladin threat with little in between cooldowns, however increasing that burst would also fit very well) to allow better scaling with the end-game content.

Seal of Vengence is an odd seal, its very effective at low spell damage, has a low co-efficient (so scales worse than other judgements and seals) and is Alliance only, oh and its a stacking debuff with a horrible tendency to fall off, especially in fights like Naj'entus where his shield will eat nearly all of the time on the stack making it falling off very likely. This seal should ideally be our main boss tanking seal (and should be given to the Horde side) with perhaps an increased timer (to 20s from 15 to make its reapplication and seal weaving more viable with a fast weapon), with an increased co-efficient or innate threat to allow it to remain more viable in the end game where the better co-efficient of our other seals makes the high base damage of this seal irrelevant.

-- Innate threat abilities
We have a single innate threat ability, Holy Shield, as such we are nearly 100% reliant on Holy damage as our threat source, this however means that we are very susceptible to silences, fears and other abilities that force a loss of control of our characters, during a silence only our seal strikes and reactive damage will have an effect if up, we can't cast consecration (though it may still be ticking) nor can we judge or reapply Holy Shield to remain uncrushable, in effect our threat capability drops to something closely approximating 0. Adding some baseline threat to either a Paladin or more specifically Protection Paladins would go a long way to making us more efficient on these kind of fights, which are surprisingly common, though to be honest I would prefer to have a solution to those issues than a cludged in work around.

On Baseline strikes and abilities:
We don't have any. The Protection tree basically gives us our tanking capabilities (increased threat multiplier on Righteous Fury, Holy Shield, Avenger's Shield, Blessings, increased damage and defence), as a baseline a Holy Paladin or Retribution Paladins don't tank. Moving some of this capability into the base line makes a hybrid spec more viable and gives rise to more capability to off-tank with a viable roll once we have done our tanking. The lack of baseline strikes reduces protection, like retribution to a simple rotation (made more difficult by overlapping timers, and very specific global cooldown windows), adding a few baseline strikes to diversify the rotation and add utility would add a nice aspect to the class.

On Rotations and reactions:
One of the most horribly interesting design factors of Paladins is that we work wonderfully when things go right, and lack abilities when it goes wrong. In some cases such as anti-tank-death abilities such as last stand this is a bad concept, Lay on Hands is a nice ability however cannot prevent our death, it can restore us before or after it, but if a bad set of hits comes in we are dead, Ardent Defender is also not reliable as a form of death-avoidance. The Paladin rotation is actually quite complex with the overlap of Holy Shield (uncrushable), Consecration (threat), Judgements (threat, utility), and boss specific tools (Exorcism, Holy Wrath, Avenger's shield, though the latter two both have cast times). In general I would like to see the rotation have more options in its 2-3 global cooldown slots however to retain its lack of utility when things go wrong to force Paladins to be good and react before things go wrong rather than relying on fast cooldown taunts and AoE taunts to make a bad situation better.

On Stats:
Paladins are a lot like Warriors, we want Dodge, Parry, Defence, Block Value, Expertise, Hit Rating, and Stamina but we also want Spell Damage, some Intellect, and some Spell Hit Rating.
Our set of stats we want is wider than those a warrior wants (ideally they would like Strength as well for additional threat, as white damage is a proportion of their threat unlike ours). This diversification of stats means Paladin gear is often badly optimised for us, or penalises us (high spell damage = fewer other stats), adding some synergy between our defensive stats and our threat stats would greatly aid this situation, key to this really is block value, for warriors this is defence and threat through shield block, for us its only defence. Through an improvement to Blessing of Sanctuary we could have an offensively scaling defensive ability that would reduce the number of stats required on Paladin gear to offer mitigation, synergy is really the key to making tanking easier on all classes.

On Silences, fears and losing control:
Paladins are an anti-undead and demon class, yet we are the most susceptible to fear and terror, Warriors have the capability to avoid fear once every 30s, and Druids maintain the majority of their damage reduction irrespective of their facing. Paladins however lose our active mitigation, meaning we become crushable (Teron Gorefiend will hit you for 15K crushing, crushes are bad for tanks, but also are a good mechanic, they force us to prioritise defence over offence). Realistically adding a baseline fear resistance won't help us, we will still eat fear wards as the primary way of dealing with these fears as a % chance is not reliable, ideally a seal, blessing or even a baseline immunity to fear and terror caused by undead / demons would be the solution, giving us the opportunity to live up to our reputation.

Silences are bad, all Paladin abilities are spells, with a silence up we can't generate threat, be uncrushable or react. Again it would be nice if there was some way out of this for us reliably (likely deep within Protection to ensure our DPS and Healing trees are affected as other classes are) or some kind of inclusion of Physical threat and survival tools allowing us to at least survive silences if not maintain our threat cycle.

On Gimmick fights:
Paladins have tanked all of the content in the game, and every phase of every boss, so its doable. The issue I have is the number of gimmick fights that exist that require spell reflect or have a much worse effect on mana-based tanks (silences, mana drain, etc) than on rage based tanks. While I am ok with gimmick fights in general as they force a diversified tank population within a guild, I think the gimmicks need to suit Druids and Paladins as well, giving us fights where rage based tanks find it incredibly difficult, where a Druid's abilities are very important (threat can only be built while he is immune to damage, so bleeds are needed?) or even a boss thats immune to physical damage, meaning you require a Paladin tank or a very good kite rotation to make it work (could simply be immune to physical threat to allow melee classes a role in the fight, however without a spell damage tank / kite he will simply kill the melee quickly). Gimmicks need to be present for all tanks or taken out, without that it simply leads to the idea of requiring the gimmick tank, and generally to letting them tank as the main tanks since you can guarantee they will be present.

On Our offspec role:
In most cases we are an off-spec healer, as our talents choices in Retribution do not tend to pick up the majority damage abilities such as Seal of Command, in holy-offspec we have similar healing potential to a Holy Paladin, however we lack stamina. In tank gear in contrast our heals are very weak and we add very little to an encounter. Assuming off-healing is the route we are to take adding to a solid tank-ability like Improved Righteous Fury (though moving it up within the protection tree) some kind of increased healing capability would allow us to be much more effective and beneficial to a raid when not tanking. Drawing in our protection tree would also allow us to effectively increase the number of talents in holy, however to be honest if I had more points they would go in retribution to increase my threat potential while I am tanking, any addition in this role really needs to be transparent to the holy tree otherwise the abilities will be skipped in the rush to effectively tank.