You can't have the current expansion in these polls, because people will always choose the current expansion.
WoD may have been a terrible expansion with so much cut out, but leveling was really well done and the raids were a blast. That saved it for me upon reflection. I chose Cataclysm, because although Firelands was an awesome raid and I had a lot of fun in the first few weeks of un-nerfed dungeons...
1) The other raids were absolutely forgettable.
2) Grim Batol has a "gated path" down near the final boss that looks like it could have been a raid entrance, except lol it's not. Just a tease.
3) Uldum was a major missed opportunity. The zone is gorgeous and really well done, and I didn't notice that until BfA when I went there for dailies. In Cata, it was wasted on an poorly done endless Indiana Jones reference.
4) Twilight Highlands should have brought Wildhammer customizations for Dwarves and Orc customizations too. Missed opportunity.
5) Vash'jir could have been awesome, but "oh, we're not going to finish the story of Neptulon... ever, kthnxbye here's a fake raid entrance" is probably the worst in-game storyline offense in WoW history and this includes putting Kargath as a throwaway boss in WoD. It's literally too late to do anything about it now. Missed opportunity. Also, there are GIANT ANCIENT SHELL CREATURES IN THE OCEAN. Why are they never referenced again? Who are they? What are they? We'll never know because we helped one die and the other one was just like "thanks, heroes, I'm going to sit here and be mysterious forever".
6) Deepholm required flying, and because of that became some crazy disjointed mess of "quest here now quest there oh look twilight cult, and earthen? and..." WHO CARES this place is a mess.
7) Green Jesus. They built up Thrall to be someone important, he did his thing, promoted Green Hitler to take his job, and when it came down to it, violated the whole concept of the Mak'gora like a little bitch. I know that the latter part happened in WoD, but it all follows from the disaster that was Cata.
8) And my final point, though there's probably a lot more points that matter: Murozond's defeat is way too final for the way that the bronze dragonflight was all "timey-wimey". Fuck, even Chromie makes fun of the fact that she doesn't know if every time she meets you is the first time she's ever met you. Murozond's death was time-travel bullshit on the level of the entirety of WoD.
- - - Updated - - -
As it has always been so. Orcs were already savages before they drank the Blood of Mannoroth. Trolls are actual-factual cannibals who only stopped cannibalizing each other because they wanted the Horde to protect them. The Forsaken are plague-creating "death to the living" types. Blood Elves are power junkies whose connection to the Horde was always tenuously explained. The only "honorable" race is the Tauren, but they are herd animals and just go about doing what everyone else does so they get eaten last.
"Honor" in the Horde died finally when Thrall showed that a Mak'gora meant nothing at all. They were always the bad guys who hid behind a few nice words.