Ravious’s trinity and beyond discussion reminds me: buffing is a lot more fun than healing. City of Heroes will always have a place in my heart because of how awesome Kinetics is, especially at high levels. Buffing is less visible than putting green numbers over folks’ heads, and you cannot slap a DPS meter-equivalent on it, but it is more fun for both the buffer and the buffed (than the healer and the healed).
You know the litany against healers, in design and in playing one and in needing one, so skip that. Apart from enjoying the resource management game of the little bars you watch, the big fun in being a healer is making your friends limitless gods that go toe-to-toe with Cthonic horrors and win. Sure, you could do that by pretending you are a battery and re-filling the little bars every time the big bad all but one-shots your tank, while your other friends plink away its health, but why not actually make your friends limitless gods? Buff their defenses so that they can take the hits without constant healing, buff their regeneration to cover the gap, and buff their attacks so they swing more often and put really big numbers over their enemies’ heads. Cut the umbilical cord. (Debuffing does about the same, although something within me loves helping my friends more than hurting my foes, even if I am helping my friends hurt my foes.)
But why should I go on at length when we have this view from D&D?