My cleric was TR'd right before the update. My last raid was a Shroud with a spellsinger bard. I had 1800 or so spell points, the bard had around 1400. We completed with half of my spell bar intact. Note this was Shroud and I was the only divine caster in the group.
I cast Heal probably around 2 or 3 times the entire raid. I never cast mass heal.
I've been playing for six years and have probably healed more raids on my bard than you have ever even been in. You think the problem with your healing has to do with how much your heal spell is hitting for? I can tell you that is not the problem, if a problem actually even cropped up. I have been in countless raids, and in the vast majority of them the cleric is using the wrong spells, always quickened and maximized or empowered, and is constantly overhealing.
Any raid that takes a long drawn out affair of healing a tank is usually done with scrolls. Scroll healing was bugged for quite a while after the update and was providing massively more healing than it was supposed to. Yet I'm supposed to believe your raid healing was massively nerfed from your experiential perspective? Radiant servant aura (and blast to a lesser degree) is the biggest easy button ever put in this game, taking precedence over spellsong vigor even (due to the fact that the PrE regenerates the freakin uses). Clerics (including my own) are not getting any sympathy from me, regardless of nerfs.
Keep the whining up, though (not). The constant griping and moaning about intended game mechanic changes will likely drown out any valid complaints.
EDIT: BTW, scroll healing is STILL bugged, I just checked.