I'd argue that lore-wise applying debuffs to the enemy should really have been the forte of warlocks, but... meh
Mages have become (as has been mentioned elsewhere) the logistics class: transport and catering. It's sad, but.. I'm starting to enjoy Fortuna again, though I know I can't compete on pure DPS with our raiding locks and hunters there is the fact that Polymorph is one of the most useful forms of crowd control (more predictable than fear, no diminishing returns like traps). Less a mighty wizard, more the guy who's sometimes useful to have tagging along
But I digress - 2k DPS is perfectly attainable by mages in the correct circumstances, and single target DPS ain't one of them.