The latest WoW expansion has some of the best music I ever heard in any game, but I'm afraid none of that would fit D3 by a long shot. Luckily, they seem to be trying really hard to reference the Tristram theme in the new music (the progression that reoccurs in every single D2 and D3 track heard so far minus most of A5 music). And I was also impressed by the minimalistic atmosphere track heard in the dungeon for a while. I suppose most of the interior music in the actual game will be in that style (like the music from the Tristram page on the D3 site).
the progression that reoccurs in every single D2 and D3 track heard so far
Not true at all, Dime. That progression isn't referenced in a bunch of tracks - harem, the arcane sanctuary stuff (which is 12-tone), maggot, and sewers come to mind instantly just when thinking of the act 2 music, though I'm sure many more also don't reference that theme. As usual, your sweeping generalizations are totally groundless.