I don’t want to spam it since I’ve posted about it in other threads, but if you check my post history, I have hard data that mages are in a freefall right now in terms of heroic raiding representation.
TL;DR
Mages are the least represented class in the game right now in heroic raiding by a large margin. They’re down to 5.51% representation, with the next lowest being monk at 6.07%