And what if you click "no" for your AOO thinking that you'll have to use your shield or counterspell but no one attacks you and the wizard cast a cantrip that doesn't worth your spellslot ?
Because we are talking about different problems. Aside for the fact that the basic AoE is arguably the least problematic type of of reaction to "waste", I'm not talking just about missing a chance to act, I'm talking about making a mental image of how the combat should go and then having an entirely different outcome. Case in point: I set my counterspell on a caster, and then this caster decides to use a cantrip or do a staff melee attack, while the OTHER caster in the same fight goes for a fireball. How is that any better than the dumb toggle system we have currently, in the end? Unless your idea of pre-planning would include a set of script conditions like a "IF THEN ELSE" (which incidentally would make it more effective at the price of being exponentially more cumbersome and slow).
If I had a "manual confirmation system" (or as you call it "a pop-up system) on the other hand I'd be able to REACT on a case-by-case basis.
In the end it's just a matter of a few seconds I'd personnaly rather spend to really play than to answer pops-up.
I got that you are really adamant in being against this stuff for some bizarre reason, and that's your prerogative, but I'm not sure how "answering a pop-up" (or whatever may replace it) should count any single bit as a less legitimate part of "playing the game". Well, no need to answer as it's a rhetorical question: it's not.