We use stop hits all the time. If it’s a left jab it’s usually followed with an overhand right, unless they go into a Philly shell, which we use all the time as well. If they shell off a stop hit it depends on where you both are relative to each other, and what you have in your tool box.
We use a lot of front foot sidekicks to the body as stop hits as well.
As for leaving a technique hanging out there, unless you’re doing it on purpose as a setup, you might end up paying for it.
We always used to tell students “You leave that hanging against a Kung Fu guy or a wrestler it ain’t going to be pretty, he’s going to own you.”