We should really organise this sometime. A full archer team vs a mix of shielders, pole/2h and cav and an open map.
More than likely to happen with the terrible balance system
Just get archers to all put one banner on, and everyone else put another banner one. Archers vs all and see what happens (I'd bet heavily against the archers, but that's only if the enemy has shields).
Being able to hit people before they can hit you is a huge strength. And I agree with no rules just play, most arrows should glance on plate armor (should have a small random chance to do damage to signify hitting a piece of the plate that is weak).
That's why it's very important to protect your own archers and crossbows.