The easiest method to deal with archers is block line of sight:
Cover and Concealment are the easiest. Strangely, by the rules, concealment is better because it gives a %miss chance. Cover just grants an AC bonus that most archers can overcome. NPCs as a general rule should always take advantage of natural cover unless they are in a barren landscape.
Other more elaborate forms of concealment come from spells such as Obscuring Mist and from alchemical smoke sticks. Tower shields were also historically used for cover from missile fire.
Protection from Arrows is a fairly useless spell so don't rely on it. Wind Wall on the other hand is a wonderful protection from missile fire. Combattants and melee attacks can pass through but missile fire can't.
Counterbattery fire also works well. Have NPCs wth bows or something else return fire.
BTW, why are you so reluctant to sunder the bow? You are declining to use the most effective available means of keeping archers in line then wondering why you can't keep archers in line. In one of the games I play in, the DM regularly sunders the archer's bow if he is foolish enough to use it within range of a melee combattant's charge attack. The nice thing about this tactic is that the archer can't counter the sunder attack very well.
Tzarevitch