My thoughts were just to leave them as they are. The longbow stayed the same, while personal protection got better and far more common. By the 15th Century there would be few men on the field without the same protection as a man at arms of the early 13th-14th Centuries, so a longbow in say 1450 was probably as useful as a bow in 1250-ish.
Obviously it's a different story in the 14th Century, but as I have no interest in that I don't worry about it.
I might be tempted to give them the mixed weapon ability as the expert upgrade and keep the range at full. This allows you to represent two classes of archer, one of which is more capable in melee than the other.