I'm not a big fan and player of D&D but we talked about this in another thread.
I totally understand your point of view. This "real time" mecanics of the rules really seems to be a part of how battles feels like in p&p.
And this is something that really looks great to me because it gives the feeling you're in something more accurate to the reality of batlles. If someone is trying to hit you, you're not totally an ice cube waiting to take the damages... especially if you have powers I guess

I really think that a Baldur's Gate 3 games using the last version of D&D deserve news in it's mecanics and this looks like the perfect opportunity to bring TB to it's next step.
I only see 2 "realistic" solutions for more dynamic combats using the rules you talked about :
- Reactions are not skills you have to click to enable but an AI you set up to custom the conditions that activate the reactions.
- Something like a slowing down of the time when you're attacked and a pop-up that appears to ask you if you wan't to do something or not.
I think the first solution is way better.
This is something I never really saw in games and this looks like you're more accurate to the rules.
This thing you can read is something that always bothered me when I saw the game are going to be a strict classical TB game.
I think BG3 deserve another great evolution in Larian's combat mecanics, such as DoS1 and 2 were.