i really don't agree with the whole syringe guns should heal idea. with the crossbow its a single bolt so you have a decent idea of how much hp your opponent just got if he gets arrowed, but with healing syringes you'd have little to no idea.
there's also the point that someone else made that if you're gonna sit there syringe gunning your teammate you may as well just beam them because the whole point of arrows are long range/burst heals which needles wouldnt be able to do lol