I don't mind it really. I am a caster and, unlike wrath, I don't have unlimited mana anymore.
This means sometimes I have to drink, especially if people are doing silly things during a fight and not CC'ing, interrupting spells, or getting out of the fire.
The above stuff isn't really new. Us healers have been complaining about this stuff for a long time, but now it makes us go oom when people do these things consistently on each pull.
At the start of instances now, I've been reminding people of how much mana I have (67,976 mana) then I tell them how much my spam heal costs (6.6k or whatever) and to use CC accordingly or I'll oom.
Surprisingly, they've been listening. :D
Seems the runs I do without mentioning that become a huge aoe fest of sloppiness!
Maybe throwing a quick little reminder at the start of instance runs with pugs will help people appreciate the mana we have (unlike wrath, where everybody kind of just did their own thing, since mana wasn't really an issue).
Just an idea.
A little unrelated below, but...
For my two CP, I LOVE Cata healing!