There has been quite a bit of talk on the forums about the various spells each of the healing classes have available to them and how those might be expanded in Cataclysm. One poster asked when we'll see healing variants of some various DPS spells like Cone of Healing or Rain of Healing (which was actually announced for Shaman). This led to a fun little conversation here at WoW.com between Dawn Moore, Chase Christian, Elizabeth Harper and myself.
We came up with ideas like Holyfiend, a pet that healed people. You could either target it or set it to "aggressive" and it would heal people at random. Another idea was a talent turning a paladin's Consecration into an area healing effect that ticked when stood in (standing in stuff on the floor is good?). There was also the idea of creating a healing wand similar to the healing rod from Final Fantasy VI that did healing instead of damage on the target you attacked.
What would be some interesting mechanics you'd like to see turned into a healing ability? Would you turn the moonkin's little treants into mini resto druids? How about something like Pestilence that spread your heal over time spells to the rest of your party?