By class roles I mean the aspect of a tank and DPS/healer. Obviously damage dealers and healers will always be there, but is the idea of a tank and tanking outdated? Non-organized PvE groups are disassembled over and over because 1 tank leaves or because they can't find one to begin with. Tanks seem to be the threshold holding back a lot of growth in PvE. I know some games have already taken steps towards reducing dependence on a tank role.
I could see WoW(if the Devs wished, not that they would) evolving to not having a defined tank for the group. Again, not saying they'd ever do it, but the capability is there. I played a Holy Pally at the end of Wrath when the pre-Cata patch had already come out(meaning I was OP as f**k). During that time I tanked and healed(at the same time) the heroic 5 mans as holy. For the most part I could keep aggro, but even when I didn't I was able to heal the DPS that the mobs were focused on.
To me, the whole feel of those runs was more fun. The fights felt more like an actual fight, like a brawl, not just DPS mindlessly stabbing some mobs back while the mob(for some reason) couldn't stop attacking the tank. DPS with mobs on them feel more inclined to use abilities not in their standard rotation, which made the gameplay more fun. If a mage got targeted, he'd want to use his frost nova and such, a rogue his evasion, pally his bubble/heal/cc, etc. To me, that's how the game SHOULD play. Every ability in your spellbook should be in the mix in both PvE and PvP. And I think it's the tank oriented style of PvE that takes that away.
Just a thought. I think outdated is the right word for this. Just tired of seeing groups so reliant on finding a tank. And I think that we have been playing games like this for so long that we kind of forget that all the mobs focusing 1 person is kind of nutty. Again, not saying WoW should do this or I want it to, just that I think it has the capability for a different kind of gameplay from what I saw with that Holy Pally.