Bards (Rogue) are mostly supporters, with great buffs, a little bit of damage and some healing. They will never be "main" healers.
Chloromancers (Mage) are also supporters, but afaik they are more healing, less buffing than Bards. If they can "main" heal, no, not right now. Maybe later when they are overgeared. Now im talking lvl 50 T1-T2 expert (like heroic in wow) dungeons.
Clerics are the only viable "main" healer at this stage. Im playing one btw, and its awesome. And you can easily lvl up with some dps souls. Inquisitor is a great dps soul, try it out. Also heard great things about the Shaman soul as a solo-dps'er, but havent tried it out.