nah CDPR is too lazy for this they probably won't even give us a classic save game import which means our previous choices won't matter
Combinatorics is not very friendly to this idea.
As I saw Dragon age (not Inquisition), it's just a game with decisions, but it's still very linear - corridor game with some choices and script outcomes - the game is not realistic for me. If you choose A, A will happen - Witcher is completely different - just few clear decissions and more hardly predectable (or unpredectable) outcomes - that means much more work to make that properly. If you want to do that properly and count with all outcomes, they won't finish it till 2020.
It's not so hard to estimate number of possibilities (I will count just with 3 choices per game..) 3^3 ... 27 outcomes in W3, but 3 is very small number and 4 would give you 64 outcomes. And you have some options:
1) reduce those choices during game ... you will not avoid disappointment of players wchich chosed them
2) make same outcomes for several decissions ... but where will be that benefit of more choices
3) reduce impact of decissions between games ... not perfect, but I think the best choice
4) no impact on next game
5) give players "cheap style" outcomes - different, but unrealistic states of world supported with some comment, pictures etc., you have to sacrifice quality over quantity
6) ... you can add some ideas..