Normally I would spend a bit more time writing these, but since this is simple I am just going to one draft it.
Simply put, elves have a stupid habit of changing from melee to range when their target gets just out of reach. This is especially problematic with faster enemies and those with knockback. The elves get stuck in a loop of melee/bow/melee/bow doing little to no damage until they die. I have two suggestions as to how this can be rectified.
1. The simplest solution: change the distance that elves will change from bow to melee so there is less chance of the elves being knock silly with a knockback stick and changing to their bows.
2. Give elves the ability to be ranged or melee Warriors in their gui. Perhaps even a horn of command especially for elves telling them to change weapons so as to more precisely control when they change their weapons.
That is all folks. If you disagree with my logic hire one elf and one Orc and equip the Orc with a knockback weapon. Then watch as the elf is mutilated while he/she fumbles with their weapons.