I knew Guild Wars 2 was attempting a game without a healer, one perk for a such a system they mentioned, is that there would be shorter waiting times when making a party. As for tanking, control is their style of tanking. Blinding and knocking down opponents for example, its kind of similar to Guild Wars now. But can this system work effectively and not turn into a frustration curve over a difficulty curve through progression?
Typically in games, higher level enemies get more attacks and do more damage. Without a healer topping you off manically you're going to die. In Guild Wars 2, a support spec'd player or collectively as a group, (where you are going to have to manage spells,) it's your job to protect players from incoming damage. Putting it this perspective, it's a glorified healer but something I like the idea of. But a concern I have is that, there might be a stage of the content where someone just becomes a gimped healer. The optimal PvE monk's of Guild Wars has a balance of healing and protective spells, something I can't imagine a RPG non turn based game not to have without removing difficulty.
As for a control role, I really like the idea of such a role. When deciding which profession to pick back in 2005 for Guild Wars, I interpreted the Mesmer would be the spine of a team in battle, preventing enemy attacks and weakening opponents (It was something like that in PvE :P). With the game to be designed to account players controlling enemies it sounds a clever model opposed to a player taking all the damage and as well its coincide with the support model.
They really need to nail this for it to work in my opinion. A simple tank/heal/damage model is a tried and tested way, ArenaNet have pushed the boat out and are going into a new level of combat balancing, I hope it works!
edit:grammar
Edited, Nov 22nd 2010 9:08am by Kernave