I kinda had the same general idea of nerfing ammo regen a month ago, and even got some likes.
Your suggestion in particular has a flaw though - it’s gonna make melee careers as strong in ranged combat as ranged classes, cause they will be able to regain as much armor if not more. This could be balanced out, but would require a complete rebalance of all ranged career talents.
There is a simpler solution of limiting party to 2 ranged careers, which could at least work as a temporary workaround. It has now flaws, except that community might not going to like that. 