It's nothing to hold your breath over (you'll pass out way before we see any changes on the realms), but Ghostcrawler says that healing is due for a revamp in terms of "fun," and while he says it'll be "a more challenging fix because what people think is fun about healing varies and some people are pretty happy with it already," he also hints that it'll be a pretty big change. Right now, healing is basically whack-a-mole -- when someone gets hurt, you cast a heal on them -- but Blizzard may be rethinking that mechanic completely. We'll have to wait (probably quite a while) and see.
It's also interesting to note that Death Knights are a tanking class, and tanking got the revamp in Wrath of the Lich King. While some healers probably won't want to wait all the way until the next expansion, could this be a hint that we're looking at an Emerald Dream expansion, with an Arch Druid healing Hero Class, and an accompanying revamp of healing mechanics? Obviously, that's a stretch, but it makes sense, doesn't it?