I agree with you. Archers are terribly underpowered.

Luckily, it sounds like they're making them a little more deadly in Kingdoms. I hope it's a lot more deadly, frankly. (Even though I'll cry when I'm on the recieving end of a bunch of longbows. ^_^)

Just be aware that clamping the firing angle like you were planning will, in the long run, reduce their damage, since they'll make less shots which, no matter how inaccurate, might've hit something.