I have played both wow and coh.
The biggest thing you need to get used to is that in this game, is that healing plays a secondary role to damage/control/buffing/debuffing. There are powersets that will allow you to buff yourself to do over 400% more damage that normal. There are powersets that can reduce a mob's recharge rate (how fast he attacks you) to 10% of his normal. There are power sets that can do an aoe stun that locks down 20 mobs at once for 10 seconds. There are powersets that focus on doing aoe damage, on single target damage, on doing damage that also debuffs as well. Everyone is not equal. Some player's powers work well with others, some are great solo, but are blah in a group.
