This will be a disaster, after MOP heroic easy mode dungeons making a 180° turn and slapping the people that grew accustomed to the "difficultly" and maybe going back to Cata difficultly (deja vu?) will throw allot of people for a loop.
Blizz should stop sending those mixed signals every new expansion. I can already smell the pug wiping in all those dungeons a mile away and the fallout of all the whinebombs.