I remember somthing similar was suggested a while back, and wich (contrary to this one) actually made sense and a good sense of balance.
I'll just throw it back here :
-enable a max draw time for all bow. If you exceed it, your fingers get rip, the arrow falls to the ground, and ingame, you have a kick-like effect. Damn, you've hold that bow too long, and it just damn hurt. To not hinder anyone too much, put that limit at 5sec.
Will prevent thoses pointblank shooting after holding and moving during 10sec. Will not change anything to the normal hold for a little bit to feint, then shoot - archers.