I believe these things are what separates classic and live more than anything else. In vanilla, each class had a distinct and powerful identity that reflected actions only they could perform. Putting a group together for a dungeon and getting a feral druid tank and a holy paladin healer would be an entirely different experience than getting a disc priest and prot warrior. Even just changing from a priest to a druid healer would change the dungeon experience dramatically.

The fact that classes had such huge identities (as reflections of their totally unique strengths and weaknesses) was what made the game an RPG. It was also a huge part of how you gained a reputation on your server, as you weren't a "healer" - you were a "resto druid healer," which was a totally different thing than a "holy paladin healer."

There's a lot of talk about "what made it so good," and to me, this is the biggest thing. It affected the game down to its core, from grouping up quickly for a quest, to doing dungeons, to end game content (my guild had a feral druid main tank and only used the prot warrior to main tank when we absolutely had to, this made my experience insanely different from other peoples). On live this just doesn't even come close to existing. It doesn't matter if you have a paladin, warrior, demon hunter, monk, or druid tanking. They run in and smash AOE while holding agro without even trying. They're probably watching television while they're doing it. Same thing for healer. Because of this, there is NO class identity, and worse, no PLAYER identity because not only does every class play exactly the same, every PLAYER plays the exact same, too.

It's so refreshing to actually get the chance to have unique identities and abilities in WoW again. Really looking forward to this.