The whole reflected damage thing needs to go anyway.
I can't even enjoy a solo game without getting reflect-killed because the AI teammates walk in fire, stand beside my C4 when I throw it and sometimes just won't move, because fearing powerful explosions is for pussies... So I blow them up and get rekt in the process by the hand of god or something.
Punishement for team killing should be there, only to punish toxic players. Something as simple as a "Press F1 to forgive or F2 not to forgive" when you get team-killed, with a kick if you get two unforgiven TKs, would be so much better imo. Sure it could also be abused, but there is no system that can't be abused by people who just want to disrupt gameplay, so...
That's a major positive thing you mentioned. Makes people more polite, and that's a good thing.
Wonder why it's not already implanted in the game.
Also, I don't even see why TK punishement is a thing in solo play. They're bots you play with. When they get stuck or when they're acting overly dumb, it can be quite practical to shoot them... But you can't do that, for some reason. Bots have feelings too, I guess ¯_(ツ)_/¯