I admit Blizzard has gotten slightly better at shaping up their villains. You still have the 100% bad guys like Garrosh and Deathwing, but we went from the typical enemy to more conflicted ones. Sargeras had this great design to purge the universe of corruption, N'zoth hints at him saving the world (might be a lie, but often old god speeches are actually pretty reliable).
However, even if their plan has some nobility to it, it usually involves our annihilation, so they cannot really be good guys.