Sure Lindy. Illidan didn't drink from the Skull of Gul'dan, kill Tichondrius, bring the Naga back to the surface world, find the Eye of Sargeras, come a hell of a lot closer than anyone else to destroying the Frozen Throne, unite the Naga, Blood Elves, and Draenei, conquer Outland from Magtheridon and the corrupted Orcs, and has now plunged into insanity due to losing to the only person to actually properly defeat him, Arthas.
Yep, none of that happened.
That all said, the best villain is clearly Seymour.