I haven't played my healer much but I know my wife is having issues on some fronts. It depends-it seems that if you have strong healing in your raid, its less an issue. They are not just trying to make mana an issue but push healers away from frantically spamming spells repeatedly.
When your healing is deficient for the content, you'll suffer. We had 5 equally 'decent' healers yesterday. None spectacular but above average, I think. And 2 very weak ones for Mother yesterday. And wow....my wife was in mana trouble the whole time. I might be ill specced for a heavy damage fight like that with zero talented avoidance.
your hat may be nice, but I have the little white tank top that says Legendary right across my boobs. I win. (or more correctly, H wins)