How to nerf CoH: discussing the options.

So, Blizzard decided CoH needs a nerf. I'm fine with that, it's clearly OP now. Question is, how to nerf it.

Option 1: give it a cooldown. I'd rather not see this happen, because it dumbs down the class. Players will still be spamming it, just less often.

Option 2: give it a cast time. I guess that makes it more like chain heal, it's a better solution then the CD but I think there's a better one even, which would be...

Option 3: increase mana cost on spamming. On each CoH cast, the priest gets a debuff, increasing the cost of the next CoH by 20%, stacking 5 times. Debuff lasts 10 seconds. (I just pulled those numbers out of my ass, feel free to balance them properly). This way, the priest always has the option to use CoH, but is severly punished for spamming it randomly at inappropriate times. I'd love this one to be implemented.

(added) Option 4: make it group based again. It does two things: it makes the spell different from Chain Heal, so it's good for diversity, and it makes it more situational, so less OP when spammed inappropriate. I doubt Blizzard would like this option, but I'm adding it anyway for discussion.

Please feel free to comment on my options, or post your own.