Sadly, I can't think of a better option to find a happy medium between the two reaction systems other than a toggle to switch between them
I was under an impression that happy medium is what most are campaigning for.
Smite and other stuff like that aren't reactions - in general I don't mind stuff like that getting streamlined a bit as they are manually initiated by players - even if I loose a bit of control it is still a decent tradeoff. With bardic inspiration I don't mind attack buff, as it's easy to see its impact and I have control over it - it is actual reactions, an action initiated during enemy's turn, that are a problem.
I never minded stuff like rogues dodge - either I don't care what I use reaction for, and will use it when the occasion appears, or I want to use specific reaction for specific enemy and am glad that I am able to do so. I can imagine xountetspell being of annoyance (base campaign had very few Spellcasters, didn't get deep into expansion enough to see those). But:
I still believe that Solasta implementation and presentation is the problem, not the system itself. The reaction popup is placed very poorly - on the top of the screen, place your mouse is unlikely to be anywhere near around as interactable UI is at the bottom. Dismissing it is a hassle but not because it asks yes/no, but because it does it poorly. Make it easier to dismiss the prompt (like RMB anywhere on the screen) and present it better and it will be just fine.
