I'm keeping high hopes that
1) It's actually announced - seasons for D3 could only go so far. While an expansion would add new life into D3, I think it would be better for the "tarnished" image that some still hold of D3 be put to rest, and to try and re-invigorate the franchise with a new title.
2) It's more D2 than D3 art-wise. While the dark-themed D2 still holds many fond memories for me, I really believe the lighting engine in the game was more to blame than anything

D3, while a lot lighter, was more realistic. The best I think I would hope for now is a possible tone-down on the colour palette they choose, and less anime-type-giant-shoulder armour.
I'd also like to see a character select screen more like D2.... something that small made me form more of an attachment to my character than the whole play-through in D3. And CAAAAAAAAAAAAAAAAAAAAAAIN!!!!!
Stay a while....