Where skill comes into play:
It's widely agreed that the Rogue class has the highest skill cap of any in WoW. By skill cap, I'm referring to the idea that the level of skill required to master our assassination and stealth techniques takes more effort than any other class. It's important to note that this does not mean that Rogues are more skilled, or that other classes require less skill. My statement is simply that it takes more skill to completely master every facet of Rogue play.
While we can speculate on who takes the least skill, I began examining why the ninja class requires so much effort to play. I came up with the answer: tons of spells. We've got so many skills and abilities that can be used both offensively and defensively that are all necessary on a moment's notice. I have about 40 spells all key bound for instant access. Each of these have a specific purpose, and typically a cooldown attached.
While our ability to evade damage has been part of our class' definition, it has reached the point where we can no longer be balanced around the idea of using our cooldowns to survive. It forces Rogues to pick up Preparation in nearly every PvP environment, and cripples us any time a mistake is made. Our survivability depends on Dismantle and Evasion versus physical classes, both of which are lackluster in this world of weapon chains and dodge rating rebalancing. Cloak of Shadows provides a 6 second window where RNG can still ruin our day, and is our only true defense against a caster.
Trying to optimize our cooldowns to survive a fight becomes the area where Rogues are able to truly showcase their skill. The most oft-mentioned example, vanishing a death coil, has become an art form in and of itself. However, the fact remain that outside of long-duration cooldowns used in quick succession, our survivability is the lowest amongst any of the classes. With so many classes playing the hybrid role, we are simply unable to react to their assaults.
Why ret paladins, hunters, and DKs need to be rethought:
Against a warrior, one would never consider using Cloak of Shadows. It provides no benefits (well, it will once we get this Glyph) currently and is a waste of time and a valuable ability. However, when fighting a paladin, or a death knight, or even a feral druid, using Cloak of Shadows becomes a key ability. This means that we'll be using both Evasion and Cloak of Shadows against a single enemy, due to their ability to assault us on multiple fronts. While some Paladin attacks are holy damage, they cannot be cloaked, and some of their attacks can't be dodged. This also translates to the Death Knight, who is capable of dealing significant damage against us regardless of which cooldowns we have active.
Rogues are still able to defeat our traditional opponents. Most casters, and many physical damage dealers will fall when ambushed from stealth. Our weakness is against classes who break the barrier of physical versus magic: truly the overpowered battle-mages of Stratholme past. Hunters have found themselves in a similar role, dealing a mix of magical and physical damage, at a distance, no less.
Pure vs hybrid:
Most of us consider the split between pure and hybrid classes to be those with a single role (DPS) and those capable of multiple roles. I would like to change this perception (for the purposes of this article) to describe those classes capable of only a single type of damage, versus those who wield magic and physical damage simultaneously. This explains the reason that Hunters, Death Knights, and Paladins currently top the SK-100 and many other brackets.
I once wondered why I seemed to be getting killed so much quicker in arena matches than in seasons past. While obviously the scale of burst vs survivability has tipped in the favor of burst, it seems that Rogues are unable to survive an assault on any front. Evasion reduces our frontal melee incoming damage by 50%, in a perfect world. However, the fact that we are still able to be stunned during evasion, and that its effects are simply negated by using spells, have nerfed its potential greatly.
Rogue spells that "don't" work:
Other classes have spells that work every time. Ice Barrier always absorbs X damage. Icebound Fortitude makes you 100% immune to stuns and you take X% less damage. Evasion may or may not reduce the amount of damage you take, and may or may not work based on who you are fighting. Ice Block always encases the mage in a block of invulnerable ice. Divine Shield always protects the paladin from all damage. Vanish occasionally removes the Rogue from sight, and is again easily countered depending on who you are playing against. Nearly every class possesses a damage-over-time effect of some kind, and an AoE as well.
Having RNG present in the majority of our defensive abilities has hurt the class as a whole. Our inability to perform consistently has caused us to be dropped for those classes capable of repeating their performance, exactly the same, every time. Warriors used to be valued for their random RNG mace stuns, and now Rogues are undervalued for when RNG trumps their reactions.
With a class defined by flashy cooldown usage and evading damage instead of mitigating it, we need more reliability in our abilities if we are going to be able to compete in the future. The new Glyph of Cloak of Shadows is a step in the right direction, adding some reliable damage reduction on demand. However, it's far too little against a world where every class has better defenses. I am hoping that Cloak of Shadows will be modified to be 100% spell immunity, and that Evasion will provide something more akin to Deflection's bonuses. I am thinking along the lines of 100% physical avoidance but 50% physical damage reduction. We'll see if we're able to overcome these obstacles come 3.1, but unless Rogues are able to find more consistent options for survival, I doubt we'll see our lifespan increase significantly.