WoD, of course.
Cata gave us a whole new Azeroth from 1-60 in addition to the new, long-requested zones, it had three dungeons in the final patch leading directly into the raid, just like ICC, and its rep grinds had actual dailies.
WoD gave us a great leveling experience... then nothing. If you were a raider, you raided. If you weren't, you just kinda sat in your Garrison, did a few dailies, tried to grind rep through mob kills alone or went back and did older content to fill your play time. Until 6.2 came out, where you got another Timeless Isle zone, with a few more dailies.
Cata just overall had more content.