Hell yea! He'll walk up in a cut scene and tell you the story about how he was saved from trist and then BAM he smacks you in the head and starts charging you precious gold pieces to identify your equipment cause when he hit you..you suddenly forgot what they were! Epic boss.
But other than that i say Meph seeing as he got the shit role in D2 (easy boss,easy to get to,dies first out of prime,fucking explodes when he dies) and seeing as Diablo failed twice i mean you'd think someone else besides Baal would get a shot...cause Baal i don't know if any of you watched the cinematics...was a queer. no offence tho

i hope they dont make the story line too retarded just for the purposes of doing something new.