I see cataclysm a failure compared to TBC, but not WoTLK. Cata is pretty much a glorifed WoTLK, took what was good about WoTLK, but also alot of bad stuff.
I perticulary good thing is that the older raids do not get desirted once the next raid concent hits. I.e. people are still playing BoT/BWD, atleast on my realm. That was one of the things I loved about TBC, could have just been that I was in a shitty guild, but we kept raiding Kara, Gruul, Mag, SSC/TK even when BT was out. Each week, cleared it all.