I think that under ideal circumstances both options would be available at the start of the game, similarly to how you choose the difficulty setting in most games.
Pillars of Eternity 2 initially only had a RTwP option but later on added an option to play the game in turn based mode. I haven't played it myself so I don't know how successful the conversion of the entire combat system turned out to be, but it seems like it'd be the best course of action if Larian wants an option for both groups of players who prefer the different types of combat.

Considering that BG3 still is in development I'd dare say this is the best point of time to add both options to the game. This way they can balance and adjust the combat encounters appropriately every time they are added to the game rather than having to go back at a later date (as was the case with POE2) and start all over with applying the second combat system to every encounter that already had been added to the game.

Last edited by Bukke; 16/06/19 11:38 AM.