The core issue is the realization i think. IRL you can just say "i want to use my reaction... ", while in a digital game it is not so simple. Well, it is simple to implement in active pause real-time combat like the old dnd games, but not in the turn-based one. The pop-ups is a bad option, because you'll play a " Close a dozens reaction pop-ups until right one" game and not the "real" one. Maybe there's a solution to make reactions work more.. "natural" in turn-based combat system, but i personally dont know how.
