They all look extremely fun, so I'm now even more undecided on what I'll be playing.
As has been said before, there's no 'Holy Trinity' (Tanker, Healer, DPSer). All professions can deal damage, support and protect each other and themselves. Some professions do it better than others (namely the Guardian profession looking to be a great protector), but they still all do it. There's no such thing as 'threat' in GW2, which is very appealing. If someone takes a big hit, it's up to them to save themselves, however, you can still help them out by blocking mobs with walls or shields, stunning them, knocking them back, interrupting them, disarming them, etc, to buy a little time. It kinda reminds me of WoW's arena at the moment. When you remove threat, it becomes a lot more intense. If you remove the healer too, it becomes a lot about teamwork.
All classes have these kind of supporting abilities, so with the scaling of enemies (the more players fighting, the harder the opponents become), players should have to work together well; instead of just healing the tank. In my opinion, playing this game is really going to be a lot of fun.
Edited by Joe on 27-12-2011 14:07
I played Classic until I was nearly level 60. It needs The Burning Crusade really for me though. I am lurking around Daggerspine again for a while, trying to get used to the changes lol