The roles are supposed to be ranged DPS (1), melee dps (2), control (3), support (4).

Ranged DPS could be achieved through unremovable hex-like degeneration debuffs. Essentially spam DoTs. It can also be done through more mesmer-like means, like debuffing people with empathy and such (every time target attacks, it takes damage). Debuffs could be unremovable, as they're supposed to be damage. Finally it could be done though skills like energy surge, that would always do max damage and not burn any energy, as there is none in the game.

Melee DPS will probably be achieved via illusionary weaponry and new skills assigned to it.

Control can be slow debuffs, empathy/backfire style skills, perhaps through conditions. I doubt we're going to get diversion .

Support is a bit of unknown. Inspiration magic skills were support, but they typically supported you, not your partners.