Fire arrows are just a bad idea.
But the team colored arrow feathers sounds awesome! The feathers don't even have to be bright, garish colors. Your team could be colored green, and the enemy team could have red arrows. I believe that's how the "X killed Y" thing in the bottom left corner of the screen does it, with friendly kills being green and enemy kills being red.
Or not. Friendly team could be blue, and enemy team could be red.
Or, team A could be red, and team B could be blue.