I distinctly recall Ghostcrawler's commentary prior to Cataclysm, particularly when discussing what he termed "the PvP arms race".
It interested me at the time, because it was something that I felt had a profound impact on PvE and wasn't just reserved for those duking it out in arenas and battlegrounds. The basic premise is that each class needed to have a counter to something that was happening to them, roughly giving them a chance for survival. Stuns, roots, CC and high damage were all things that had to be countered in some way, so classes were given utility to allow this while attempts were also made to ensure each class had both offensive and defensive options.
That's a terrible opening paragraph; but simply put, Ghostcrawler was worried that so many counter-counter-counter-counters were being used among classes in PvP, and it wasn't making for decent or enjoyable gameplay.
What struck me was that this concept of the arms race first reared its head for me during the transition from Outland to Northrend, and it was in PvE. I know many readers will recall the difference between the Protection warrior and the Protection paladin in The Burning Crusade; while the warrior had the cooldowns, mitigation and single-target threat to be the most effective boss tanks, the paladin was far and away the better option for any trash duties and/or heroic instances. A healer could literally spam a paladin, safe in the knowledge that they wouldn't get aggro by doing so.
When our adventures started in Northrend, it was decided that each tank should be capable of boss tanking. This meant that the traditional tools required for boss tanking (cooldowns, mitigation, threat generation etc) were given to all of the tanks in order to allow them to fulfil the role. What was NOT rebalanced, however, was the significant advantage the paladin still had in AoE situations, both with regard to threat generation and an unusually high chance to block. What essentially happened was that the erstwhile reason for using a warrior to tank bosses was gone, and he was still the inferior choice for trash/heroic dungeon tanking.
This probably reeks of QQ.
It should not be argued that warriors weren't viable tanks during Wrath of the Lich King. For the vast majority of the playerbase, success was not dependent upon the class of your tank; it was dependent upon his ability as a player. This gave rise to the oft-repeated mantra of "warriors are fine", and we've been hearing similar repeats of this cry ever since. If something is viable for the content, and your raid isn't being held back, then the spec is "fine" and you shouldn't complain.
The problem is that "fine" does not mean "strong".
Last night was a first for me. Something happened that had never happened before and, honestly, I didn't know how to react to it. During a night of heroic Ragnaros attempts, my coveted tanking spot was given to a player deemed to be a "better" class. He wasn't a better player, nor was he a more loyal member of the guild, and he certainly wasn't a chosen elite of the guild's hierarchy. No, he was simply considered the better class choice due to how they guild intended to do the encounter.
Whether or not you can justify this isn't really important. The fact is that it happened, and it happened for a perfectly viable reason beyond favouritism or anything so petty. If each tank has the mitigation, threat and cooldowns to do the job then a raid leader has to look at what ELSE that class is bringing to the table and make a judgement on what they want the most. And at time of writing, warriors and death knights have fallen behind in this "arms race" I mentioned above.
All four tanks have the basic tools with which to do their job. Unfortunately, paladins simply have far too much utility and druids can contribute far more damage when not actually tanking anything by switching form. The fact that both also have powerful raid cooldowns, which warriors and death knights lack, is a further nail in the coffin. This is not an argument about whether or not death knights or warriors are viable tanks - I've no trepidation in saying that, to date, the best tank I've played with happens to be a death knight on an RP realm. The point I'm making is that the arms race is causing discrepancies at the highest levels of content because certain tanks have capabilities that cannot be made up for by skill.
The reason this is a problem should be obvious to anyone who's looked at the set-bonuses of the four tanking classes.
They're raid cooldowns.
Put bluntly, Divine Guardian is so strong that the developers have decided the other tanks need something similar to it in order to be competitive. Rather than simply putting Divine Guardian into the Holy tree, where it should have been from the start, other tanks are being propped up via an ugly fix that is gear dependent rather than anything to do with skill or sound judgement. The problems here are absolutely manifold when you think of the implications. If Blizzard are giving raid cooldowns to all the tanks, it's a safe assumption to say the tanks are going to need them. And if the tanks are going to need them, it's going to have a pretty horrid impact on the three classes that must net four tier pieces.
All I can say is ouch.
The arms race which the developers want to move away from, is being continued in a fashion that will STILL be painful on three out of the four tanks. Not only that, even when those tier pieces are gained you're looking at tanks giving up their personal cooldowns in order to provide raid cooldowns when the one at the head of the arms race, the paladin, is calmly deciding which piece of gear he likes the itemization of the most.
Rounding out, this has got to stop - it's not good for the game. The indication here is that raid cooldowns are going to be part of the tanking arsenal in the future, and this is another step in beefing up the tank role beyond its function. It's time to streamline class abilities in order to provide the levels of required utility, not keep strapping on more weapons. For paladins, the simplest and most elegant fix is to completely replace Aura Mastery for the Holy paladin and put Divine Guardian in its place. Other classes could also use the removal of some abilities that, quite frankly, do not add anything compelling to their gameplay at all.
If you think about it, removing abilities that don't readily have a clear niche opens up the opportunity for better abilities to be added in the next levelling jump. If we keep going down this route, we're going to end up with another UI addition in the near future.
More friggin' action bars.