example:
STOPTOSHOOT = 1
(if 1, archers must be motionless before taking shots)
Right now If I see a difficult enemy, I just arm my bow and walk around in circls for about 15 minutes. The monster never hits me. In all honesty, combat is probably one of the more boring aspects of UO.
On my shard, I could increase tension, force the players to use better tactics (ie, melee warriors defend the archers), and balance combat with a simple fix of forcing archers to remain planted while shooting.
Same check could be used on mages as well, although mages have a built in check of low mana to deal with.