Add Poisoned Arrows!
They should do less base damage, but once someone is hit, that person should take ticks of damage over time at steady intervals. Loomed poisoned arrow's should continue to damage players for longer periods of time.
Also, for each "tick" of damage taken after the arrow initially hit's, you should flinch as if you were getting hit with any other normal weapon. This would make poisoned players easier targets to take down, and might even increase teamplay!
For example, an archer could pick out a high value target, "poison" him/her with a shot, and then friendly Melee would be able to take him/her down much easier due to them flinching!