you cant put Music, Art, Story and Setting into one thing.
Best music is defenetly MoP, the setting is also best in MoP and WotLK, Storytelling is way different but it got better and better from xpac to xpac.
Its event hard to decide if the one who made the points mean, that there are good dungeons & raids or a lot of them..even if he mean both, Vanillla must have to be the best cause there are a lot mor than in every xPac, but thats just what it have to be...an expansion.
Even the World from MoP is really beautiful and has a lot of funny quests inside. The worst thing were the dailyquest flood at the beginning. Knowing that these quest exist, vanilla quest are really really bad, same in TBC!
And the community-point.....the comm was never good imo. I can remember how some laughed about you, cause you are not in BWL and still trying MC. Starting-Event from AQ, where poeple farmed the stuff to open the gates and selled it at the AH...Asshole-Comm imo!
You see....