I hate xbows too (arbamy old friends most) too effective for little skill involved..
As for 1slot bows: allow only one ammo per ranged... solves problem with kite archies, xbows cav, cav archer, throwers but too harsh for them so buff acuracy
Decreasing amount of missels is not a solution, and archers are accurate enougth. IMO ranged are not letting horse bundle of stickss to feel untouchable, and total gods of battlefield.
Just wonder what could happen if range will have less amount of missels: some of them will stop shooting horses. Less archers schooting horses - that will make more horses appear on battlefied. More horses - cav rape on battle servers.