Story will be Bullshit just like classic dIII. (like the black soul stone fell through heaven directly into hell where maghda already knew where to pick it up, just to convert imperius into some kind of uber hell lord because leah pierced him in act 4.)
Mystic will be added.
Mystic can add and remove sockets to existing items.
Some sort of dII runeword system will be added ( white item superior ranking already suggest that)
multiplayer will be extended to 5 player.
Avenger Class introduced. That class can pick between Int and Str/Dex skill sets.
Between Adria and Imperius, it's not like they left much room for story growth.
I actually disagree. The nebulous ending to the black soul stone leaves open any number of possibilities, right? Did Diablo die or what his soul sucked into the stone as well? Is Leah alive in there with him? There are lots of ways to go here. What happened to Adria? She just vanished. Imperius seemed pretty pissed at the end of D3.