I've observed this as well, while there are lots of mages around I met probably 10 or 15 outstanding mage players in LFR ever since it was first released for DS. I mean I don't expect much from 5 mans these days but as soon as you step into raids... seems to me like the class is being played by many more underachieving players than the average, and that even though it has one of the few specs in the game that allows easily doing good number with next to no gear (namely, Frost).