I enjoyed Cata back in the day, but I wouldn't pay to play it again.
Pre-Nerd Heroics were cool, ZG/ZA pre-nerfs were great too!I enjoyed T11 and T12 (though Firelands could have been a bit bigger like) DS was shit. ah and Tol Barad was kinda fun too, at least for the first few months.
Cataclysm, i my opinion was the turning point from "Classic" feeling to a more modern feeling, so this is why I don't want to play it again.