There is just not enough distance between me and ICC for it to live in that rosy pink nostalgia haze in my brain where the other retro raids like kara and BWL live. I don't get the warm fuzzies at the idea of going in there.
I knocked my head against the ICC wall, in 10 and 25, for 9+ months, finally taking a break from it only a month or so prior to the Cataclysm. Anexxia alone had 30+ kills of Marrowgar in 25. I'm tired of the icy winds of Northwind consuming my soul. It's going to take ma at least a solid year -- if not two-- before a big smile will come across my face when someone suggests heading in there.
Right now, I want to do new content. See new instances, kill new bosses. ICC will still be there in the morning. And I need to give it some serious space for its absence to make my heart grow fonder.