See, the 10% Clearcasting was nice, but when I'm in a group with an Intellect buff, wearing my spell damage gear, with my trusty Moonkin friend at my side, my crit chance can go as high as 20%. And I'm not even an Elemental shaman-- those who spec elemental can get a Totem of Wrath that pushes that chance 3% higher. That's almost 1/4 of our damage-casting mana that is completely free with one talent point spent in the third tier of Elemental. At that rate, I'm churning out plenty of damage with a decent (although not even close to a well-geared mage, or even a Balance druid) mana efficiency.
In fact, it's a little too efficient for the devs-- as of 2.1, Elemental Focus (the talent which provides the Clearcasting ability on a critical spell strike), will only give a chance for a "Clearcast" with a 60% reduction in mana cost. For all other classes, "Clearcasting" means 100% reduction, but for shaman, "Clearcast" now means only a 60% reduction.
As some shamans have said, there was a nerf coming somewhere in there--25% free mana is really nice, and if anyone could use it, shaman could, but it is a lot of free mana. The reason the devs did it this way is probably because they still wanted the ability to be affected by gear-- if I wanted to, I could focus on spell critical hit gear and enchants, get my crit chance even higher than 25%, and probably make up the lost mana. But a lot of shamans have trouble having a buff called "Clearcast" that doesn't actually clearcast for us. If they ask me, I'd just forget the gear thing, make it a 12% chance and leave it be. But that's just my opinion-- other shaman can feel free to rant away below.
And I haven't even mentioned enhancement shaman-- they've all become math majors because they're losing the ability to put two different ranks of weapon buffs on two different weapons. That all has to do with the proc cooldowns bumping up against having two weapons with different speeds-- those of you who are regular readers know I'm bad at math, so I'll leave it at that.
It seems like everyone faces nerfs every other patch, so I'll agree that pretty much everyone has someone to grind an axe about from time to time. But the problems with shaman are really more basic than how often we "Clearcast" (maybe it should be "Muddycast"?) or putting two ranks on dual weapons-- it's that while we've got a lot of interesting stuff at our disposal, we've still got a lot of holes in the class. From situation to situation, our skills are either useless (tremor totem is such a joke it's amazing it ever works at all), or simply nonexistent (unlike other healing/casters like druids, priests, and mages, we have no CC at all, not even in our talents).
Is the class broken by this nerf or any other? No-- I love playing my shaman, and I'll play it whether I'm getting 100% or 60% free mana from Clearcasting. We're definitely a support class-- the tanks tank, the healers heal, and the DPS hits while we're in the background here and there and doing a little bit of everything. But it would be nice to shine every once in a while-- this Clearcasting crit buff made me push out damage that even I didn't know I was capable of, and if the devs are going to take that away from us, just what are they going to give us in return?