I'll admit, I can't attest to Cataclysm, I took most of it off and didn't raid until Dragon Soul, but I went through TBC and Wrath from Karazhan/Naxx to Sunwell/ICC. The current difference is simply massive.
---------- Post added 2013-01-11 at 03:58 PM ----------
It's not my own performance and personal well being I'm worried about. I've got that covered. I'm worried about the impact on the psyche of the majority of the more casual playerbase as the expansion continues.