Unpopular Opinions:
MoP was the Best Expac in terms of basically everything.
Cata was a great Expac and only really struggled at the end with a lackluster Deathwing Fight.
Vanilla wasn't hard and is extremely overrated.
Current Talent system is better than Talent Trees ever were.
Nearly every Horde Race was created to be edgy or Savage and thus any afterthought into their Lore felt clunky or just plain bad.