Out of all the DnD versions 5e is more tailored towards Turn based play.
Honestly I would feel cheated playing a 5e based game that was RTwP. it just wouldn't work and you would lose so much. There's no way you could properly manage your turn / action economy in a 5e system and not be having to pause every 1 second if it was RTwP.
and that's just the initial low levels. What what it be like when characters are taking 4+ actions a turn (just an an example main + bonus total).. can you think of a worse nightmare than that.
I absolutely loved BG1 & BG2 I played them the day they came out. I've been playing DnD for 25+ years and my first DnD based game was fracin pool of radiance on a com64. I actually like feeling like I'm getting a Table Top Experience in my game.
So why are you even comparing a game that used AD&D as it's basis to a game using 5e as a basis. They are totally different beasts.
The turn based combat will be improved and granted it might be slow atm on super large fights, but why is everyone assuming it will always be like that when the game fully releases. Turn Based combat can flow smoothly and be fast paced.