That's an idea, as feasible as any other.
Actually, a similar idea has been developed. Some years ago, bullfrog released theme hospital (information here
) which was a game based on the construction of an hospital, and the objectives were healing as much persons as possible (it was similar to sim city, so the real objective was having much money as possible and still have everyone happy
As for the rpg idea, I don't think it'd be as appealing as world of warcraft
or games like that. Simply because violence (not that wow is about violence, but it definitely isn't about healing
) sells better than peace, that's common knowledge.
I'm not a fan of RPG's (actually, right now I only play TrackMania Nations
, the most entertaining FREE game I know), but I would more easily play wow than an rpg based on healing.
just my 2 cents