So, I had this idea.
How about instead of having friendly fire only on/off, we went beyond the bool and, when friendly fire is enabled, you can choose a certain percent of damage allies would receive? In other words, setting the preference to "15" would yield 15 percent of normal damage to teammates.
I started to work on this, but I realized it'd probably be easier and faster for Greek to do it since he's more aware of the way Slayer's systems work than I am.
Also, possibly add a point deduction for friendly fire which has a cooldown of x seconds (I was thinking 8 or 10). The cooldown time may also be a preference, however I don't think it would really need to be. This way, accidentally shooting a teammate with a shotgun wouldn't deduct as many points as shooting them once or twice with an assault rifle.
Edit: I've just fixed up my (really) old Donate Score mod, which allows players to give points to one another, to (actually work and) be directly intended for use with slayer. The new version is called Give Points (not as fancy sounding, but I'm releasing it separately on RTB).
Poll