I really hope that Larian sticks with Turn-based and doesn't give RTwP any thought. The vision that they have about BG3, to make a genuine table-top experience is not possible with RTwP. This is why WotC even approached them.
And as far as my personal taste is concerned, the few games I played that had RTwP, had frustrating gameplay because of how stupid character AI generally was and how much hand-holding I had to do to ensure they survived. I only really was able to tolerate it in DA:O and enjoy it in DA 2 because of the Tactics system implemented in those two games. DA:I Tactics system was just a much more simplified version of the previous two games and made the combat horrible again. Having to constantly pause to correct basic actions of characters was never a very enjoyable experience and in-fact allowed for the contrary to happen.
Larian made the bold move of going with Turn-based combat at a time when isometric RPGs were coming back from a long pause, and when their peers decided to play safe. They were innovative in the way they implemented certain mechanics which greatly augmented the combat system and dramatically increased the fun factor of TB. With D:OS 2, they were able to polish the system even more(combat verticality).
I would be terribly disappointed if they decide to go the RTwP route. It would be an unnecessary risk and even if well implemented I feel that it might make it a good game but not a memorable one.