Heh. You've never used it but you assume that it's all spamming one button?

Listen... exclusively spamming CoH is such an isolated thing in correctly tuned raids that listening to people QQ about it is hilarious.

CoH is tremendously OP in BC raids after 3.0... but what isn't? Before The Big Nerf my CoH healing was strong. On fights with lots of AoE damage, it was very effective (hint: that's the POINT). On mostly single-target damage fights? Hardly used it at all because, guess what, a 1k heal to a target at full health doesn't really help anybody.

Then there's PoM... I cast it all the time. Especially when I'm using CoH because that little holy loogie bounces around like crazy in those situations.

If you're a CoH priest doing nothing but hitting that button, you're either raid healing a heavy-raid-damage encounter (hi, Hex Lord!), you're ridiculously over-geared for the instance you're in, or you're not very smart and your healing numbers are going to reflect that.

If a priest were to spam CoH, as you described, he/she would go oom in a matter of seconds. As good as CoH is, it is a very mana-intensive spell and should only be used at the right moments. As a CoH priest, I still have my repetoire of Renew, Flash Heal, PoM, and GH to rely on. I cast PoM/Renew combo on tanks, GH's for anyone who needs big heals, Flash Heals on people who take moderate damage, and CoH for any aoe's. What it boils down to is whether a priest is smart enough to use the right spells while being mana-efficient at the same time. A priest who spams nothing but CoH in boss fights is a dumb priest and should be kicked from raids.

CoH, in my opinion, is fine the way it is. The mana cost itself is enough to prevent it from being spammed non-stop.