I much prefer a more cinematic flow to combat and pop-ups that freeze combat is unimmersive and therefore eeevil. Yes, even in a turn-based game. I imagine something like a slow-motion effect when reactions are applicable affording the player a short time window to decide whether to react - similar to the renegade/paragon reaction check (but in slow-mo) of Mass Effect would make for much better gameplay.
EDIT: The current rigid pre-set system is unacceptable though. If Larian decides to go with this lazy implementation, they should compensate the character with more reactions/reaction resources as you can't decide to use as situations occur and therefore likely to waste many reactions stupidly.