For me, RPG stands for ROLE play game. When you play a role, when you CAN CHOOSE how do you play the game, When there isn o pre-defined path lies ahead. Want to be a bad-ass and wipe-out entire city in Fallout? You're welcome! Want to sold your companions to slavery in P:T? Easy.
Want to be a good guy and help everyone in BG? Then do it!
Tell me, can you really make choices in Div2? No, you can't. You can't kill Talana, you can't play as Dragon Slayer, you can't join Damian. Unlike TES3, for example, you can't kill everyone (like Vivec) and made your own path, via not joining to anyone. There is no real choice.
Don't get me wrong, I don't say it is all that bad. It's just... no need to compare it with real and "serious" RPGs. D2 is good as it is.
this is why when my friends and i talk about games, we make a distinction between RPGs and action RPGs. DA, FO, BG belong to the former, DKS to the latter. which is not at all saying it isnt good. in fact, DKS is probably the closest to an RPG than any other action RPG ive seen since it at least contains some choices, unlike, for example, Diablo or Borderlands.