I don't care. At all. Okay, that's not quite true. I probably have a tiny, tiny bias in favor of RTWP, but BG3 could be an excellent game with either one.
BG2 is one of my 2 or 3 favorite games of all time. D:OS2 was an excellent game. The common thread in both games was the attention to detail in the game design that made the characters and the world feel alive.
So long as Larian doesn't pull a Dragon Age Inquisition with the combat mechanics I'm not too worried.