Acceleration time is not negligible, ever. Every action has a time cost associated with it. Do not ever take that time for granted.

You cannot police human error in text combat without, as Melon said, using some kind of randomized system. Which then makes it come down to 'who gets the lucky roll'. Again, not a good way to establish balance for something such as this which is seeking to be competitive.

This also assumes the gun wielder has absolutely no enhancements either, which they often do 'in order to compete'. If they, as well, have increased reaction times, then that makes it even harder.

Guns are fine at a higher tier. They are not fine at the tier people often use them at. That is, and will remain, my position until someone can demonstrate some math I have overlooked or calculation I've done wrong.