Do you think archangel Tyreal could have more effects on the storyline of Diablo III? He was the one who destroyed the corroupted World Stone. Could that possibly effect him? Maybe he is going to turn evil? Or possibly change him the next Diablo or even a new villain?
I think Blizzard will start new ideas here. Taking back Andariel or Duriel is fine but not new. If that would be the case, then we were supposed to see some of Diablo 1's character in Diablo II's 4th act, in hell and we didn't.
It'll be nice to see some familiar faces, even demonic ones in the third game but, I think they'll probably emphasize on new faces to make it fresh. Should Andariel, Duriel, or other characters be there, they are surely gonna be far different that what we saw from them eariler in the 2nd game.