Let The Witcher be The Witcher and let Dragon Age be Dragon Age.
Bioware's at its weakest when it's trying to mimic some other game.
I think a lot of the issues with DAI are things they could learn from their own games much less an outside source, it's why it reminds me ME1 in that it's ambitious but structurally unpolished (only ME1 at least had a great ending). If there are things Bioware could learn from CDPR it would mostly be:
1) Spend more time on animation; moving over to frostbite obviously hasn't fixed a lot of the issues Bioware has with basic animation, everybody is still sort of a statue and the main character in DAI always has a hunched look, simple things like holding objects or posture shouldn't be an issue in 2015.
2) Plan ahead on consequences so you can manage the scale best for development; this means if too many characters can die from a mission and because of that you compromise the effects of their loss then that's bad, same goes for if you plan the consequence for an action as too big to show. Big decisions need big consideration, small decisions are okay too.
Stuff like "show don't tell" is something they've excelled at in previous games, same goes for story setup. Other things like "emergence in an open world" are probably best left to learning from other developers than CDPR.