Personally, I like Wraith of the Lich King because it was the one I started with, leveling in Vanilla and Outland were still challenging and enjoyable, riding on an epic flyer was awesome. I got to fight the MOAR DOTS Onyxia, and everything in Northrend was well done. All the other expansions had their up and downs, I never really hated on the other expansions even though the non-endgame content got trivially easy. I never really hated the other expansions because they all had something special to offer, whether being randomly ganked by Deathwing in Catacylsm, the Panda expansion, the Garrison in Warlords of Draneor (no, I don't think it was that bad), or the Artifacts in Legion. The only one I really don't like is the current Battle for Azeroth, because there is virtually nothing to explore. I can take an epic flyer and it would take 10 minutes to circle it; you could solo Kul Tiraras or Zandalar in that time on a ground mount. Everything in this expansion is just given to you and I could make it from 110 to 120 just playing a few hours a night. I don't hate *everything* in the expansion. But no one other than the raiders are "feeling it". What do you think?