Who would you have return as a raid boss if...

[Pickwickman]

I would love Illidan to come back, but yes i think you're right. They like his character alot and would probaly make him an ally and do some story to remove his demonic corruption he picked up in WC3 to make him a normal elf demon hunter again.

Not really, if they bring him back the only at the moment logical way is to adress it straigth TO his demonic part. Remember, demons don't "die", they merely get sent back into the Twisting Nether. Who is to say that Illidan isn't in the Twisting Nether right now, battling the demons there?

Which would tie into a Burning Legion expansion quite well, and make him able to train new demon hunters.

Hell, we could also have Alleria Windrunner (3rd Windrunner sister) teach you another spec, Dark Ranger, since she too is trapped in the Twisting Nether, as is Anduin Lothar, who is more of a warrior than a Paladin (Sons of Lothar faction in Outland was an homage to him).

Which would make the new class for that expansion something like Purifier with Dark Ranger / Demon Hunter / XXXX Specs. Maybe 3rd one could be a type of Holy Paladin but with another way of playing.