I love BG1/2, I think they are some of the best games ever made. They brought D&D into video games and the RTwP worked excellent with the 2e rules. However, it can be a challenge to adapt 5e to it. One rogue ability is triggered by attacking an enemy who has not yet had their turn. It gives a rogue almost a guaranteed sneak attack every combat, and is crazy useful. How would this work in RTwP? How does it count an enemy's "turn"?
Also surprise seems a little strange as well. In TB, you just have an extra round before the enemy, so what happens in RTwP? Do the enemies stand still for that? And do you have to stand still if you're surprised? While it's doable, I feel like it would break the RT part for just a bit.
I've seen a lot of people talk about how you're a squad leader in RTwP and you can count on the AI for some things, which is actually crazy rewarding imo. One pretty big detail about D&D that wasn't in BG1/2 was how resourceful you could be and just kinda make it up as you go along. I know BG isn't TT D&D, but I still missed doing stupid stuff just to see if it would work. In what I've seen of BG3, I'll definitely have stupid stuff to do all the time and I'm crazy excited about that. However, custom scripting and AI in general doesn't really allow for these stupid antics. I'd have to micromanage and pause a lot, which I might as well just have TB so I don't have the micromanage part. This is just me, I know not everyone is into dumb ideas, but man do I love when it works out lol.