I assure you this is part of a larger effort, and one of many steps I am taking to improve my game.
Sure I did. For one, that benefit is not wroth bogging down the system in (4? 5?) layers of complexity.but at least this kind of system puts melee characters on a par with primary casters when it comes to sheer damage capacity. Didn't think of that, huh?
For another, you then screw them over with MAD cause you need dex to hit in melee, as well as ranged. Also, you now overpower Dex as a stat.
Finally, did you consider that monsters generally have much higher attack bonuses and damage, but far less attacks then a party? Thus, under your system they would get many more attacks and deal much more damage, essentially screwing over a CR-appropriate encounter.
Of course, you could rework the entire CR system of every monster, and also re-calculate/rework every entry to function with the new (complicated and likely confusing) combat system. No thanks.