How does people think about leaving the Reaction system the way it is now, but allow pausing to happen at any time and you can turn on/off reactions of any of your PCs in the party?

AI can do the same thing, allowed to turn on/off reactions moving into each turn of the PC. Obviously the AI won't pause to turn these on/off, it just happens in the background and you won't notice. Probably, will happen at the beginning/end of every AI action knowing who will be acting next, but that is up to how Larian want's to implement it.

I think this a good compromise to get what people are more looking for out of the Reaction system while not having Larian to completely overhaul the system.