There is a reason the survey is out before wrath is even released, and it’s a joke it’s even floated. Blizzard knows it would be the biggest flop in WoW history.
Cataclysm is the full scale paradigm shift away from being an mmo and an rpg. Class and stat homogenization, pruning of iconic class abilities, removal of class quests, LFR, transmog, flying in Azeroth, decimation of the old world, ultra linear questlines that you out level before you finish, mobs don’t hit hard and there is no danger, destruction of talent trees, etc.
Cataclysm represents everything the core audience of classic has stated for 10+ years has ruined and destroyed WoW, and nobody currently playing classic who isn’t simultaneously playing retail has even a slight interest in it.
The only sensible choice is a classic+ based on an overhauled vanilla and new content patches or expansions after naxx based on the vanilla philosophy.