probably because the way most healers are done, it doesn't get to be cool, or in the spotlight, or it takes away from something else that could be done. personally, i have an issue with all clerics being able to heal. i think that the abilities of a cleric should be limited to the nature, characteristics, and portfolio of the entity they follow.
i have one healer, a sangehirn, that also has the schtick of being a predictor. she is blind, a nod towards tradition, but as an erudite, she can overcome her limitations temporarily. she will randomly predict things for the party, npcs, and monsters. but as her prediction is an odds based one, even if she is wrong, it can be explained by juxtapositional events which beat the odds. makes for a lot of fun. with a good bluff check, she can seriously spook out mooks and minor npcs. especially when she manifests something with a visual trait. her eyes glowing with silver fire makes for good background prelude to a prophecy.