The thing is, few players want to start Cata when it's already on 4.3.4 since that patch sucks. You're going to go through all the effort, only to reach ****ty content? I don't think so. At least that's why I quit. I stopped almost immediately after 4.3 was released because the game becomes too watered down at that point.
4.0.6 was amazing. The HCs were amazing, the raids were cool and featured new mechanics, the crafted gear mattered, PvP was explosive, reputations were relevant, Tol Barad was relevant. None of these is valid for 4.3.4, with Blizzard releasing "remastered" old content. It's like that with all end-game patches, the only exception being 3.3.5.