I hate that, it is unfair, we want to help any way we can (heal and dps) and we get penalized...
There would always need to be a balance. Let's assume Cleric had no ICD in either direction, that's a pretty significant boost to an already very versatile Healer. Is it backward compared to, say, Shadow Priests in WoW (that can cancel Shadow Form automatically by casting a heal)? Sure, though the intent is the same either way. It is there to make using your DPS form a weighted decision, not something you can instantly slip in/out of on a whim - and it should be this way, one direction or the other, when dealing with stat & playstyle altering effects as a heal-capable class.