You should have read the beta threads for healing priests.
Priests: "we have severe mana issues, all we're doing is getting a handful of heals off because we're spending the entire raid encounter spamming solace for mana".
GC: "solace feels required for priests then? well, we'll just nerf solace mana return by 90%". HE LITERALLY SAID THIS in a beta thread in response to priest mana complaints.
End result? Priests get mana regen balanced hotfixed/patched in weeks after MoP release, solace remains pretty much unusable for healing priests for an entire raid tier...I believe, I had benched my priest from the EXACT SAME SHIT happening with priests when Cataclysm went live.
GC can go eff himself, after following PTR changes/beta forums for Cata and MoP I can honestly say he has no idea wtf he is doing. Not his team, HIM PERSONALLY based off of what he himself says on the forums.