Suggestion for more options

[Imp]

I could still not fire myself without getting reaction/op fire from all enemy units in range. So the best strategy in defense is to do nothing a lot of the time, and instead rely on reaction fire in the opponents turn.

I don't end up doing this very often or doing much micro managing with the Y key on ranges.
If you are heavily outnumbered not firing the odd unit is sometimes better but good use of smoke or the dust from artillery & other fires means you can normally get local superiority at least against the AI.
So most turns its all guns blazing with the exception of any units you think are still undiscovered & don't want to give away their positions.