I understand that in the past you took situations that didn't quite go as you'd hoped to heart and that at times it affected you so negatively that you had to walk away from the PC but I think, as the feedback of the community shows, you're quite alone on this one.
It's not a fair suggestion if I am being quite honest, forcing gangs to wear their colours during fights doesn't really add to roleplay in many ways, such as making it so unreasonably easy to gather information for cops.
I don't intend to insult you but when you suggest these kind of things, is it in the heat of the moment because something happened you weren't quite happy with? Because if not, did you ever play as a criminal for a longer period of time? It sometimes helps to see both sides and get some insight and also actually feel and see how it is for the people that you are making these suggestions for.
Ofc that is just me assuming you never played as a Criminal for an extended period of time. If you did, that's my bad.
Sorry if I sound rude, that is not my intention. I am just trying to understand why you would suggest something that, in my own opinion, would put other people so heavily under a disadvantage and dictate their Roleplay quite heavily. You said yourself that you don't enjoy playing as cop much anymore but do you think that the game will be more enjoyable for you by making it less enjoyable for others?