I'm looking to houserule my campaign to increase the influence a cleric's domain has over their capabilities. I've always found it silly that a cleric of a non-evil deity, even if that deity was the god of war or storms or whatever, got a bunch of healing spells they could cast spontaneously and the ability to hurt undead. I want to give my clerics more of a flavor of their individual gods and less generic healing. Pathfinder's domains are great, but I want to take it a little further. I'm very familiar with 3.5, but haven't played any Pathfinder yet so I'm looking for some advice on making some changes without altering the power level of the Cleric too drastically.
One thing I was thinking of doing is changing the spontaneous casting feature so that a cleric could spontaneously cast their Domain spells instead of Cure spells. Thoughts? Too powerful? Huge nerf? Unforeseen consequences?
Another thing I'd like to consider is swapping out the Cleric's Channel Energy class feature for something a bit more specific to their particular god/domain. Any ideas on what? How powerful is the Channel Energy feature considered, generally?