Nobody has yet been able to explain to me exactly why RTwP would not work with D&D 5e rules. Everything that can be done with TB can equally be done with RTwP. Everything. The only meaningful difference between the two systems is that in RTwP the player decides when they want the game to pause and the action to stop, whereas in TB it is built into the game when the game will be paused. Every single thing in 5e rules, including initiative and reactions and counter-spellcasting, can just as easily be handled in RTwP as in TB. So the game being TB has nothing whatsoever to do with the faithful implementation of 5e rules. An honest fan of TB should at least own up to this. The true reason for going TB is entirely, 100%, because of co-op play and a possible DM mode.
I do prefer turn based, I don't think I've tried to hide that, but I'm being honest in that I don't think they can impliment 5e rules right with RTwP. I don't say that to convince Larian as the decision has already been made, I'm just giving my reasoning why I think it will be turn based.