Quote Originally Posted by Psyren View Post
For the most part this is true, but some boss mechanics proc randomly and so having a spare/emergency ability (for when your class abilities are all on cooldown) can help, especially on a progression encounter where everyone's gear isn't quite up to snuff.

Also, some class deficiencies can be helped by racials. For example, Death Knights are weak when it comes to escape cooldowns (i.e. "run over here immediately.") The Worgen racial however gives them a speed boost, which can be the difference between your tank needing extra healing (or even a battle-rez) or not.
I'll concede that the active abilities have the potential to be more impactful than the passives, however, all raid content is designed with running it without any particular class, to say nothing of a particular race/class combination, and the utility of one set of racials is going to vary wildly with the encounter in question.

At day's end, however, I'm not talking about mechanics, I'm talking about human nature, and the character of the median WoW player. This is not a forum-crawling hardcore raider, this is the average scrub you'll run into in LFR. Those make up the overpowering majority of the WoW player base, and I'm pretty confident they're picking the race/class that pleases their sense of aesthetics.