I was listening to some of Tupac's later works (for maximum inspiration, look up Ghetto Gospel) and it's rather depressing tones about gangbanging and it gave me the inspiration for a gritty gangster rpg. Think This War of Mine levels of grittiness, it deconstructs everything we think of the gangster lifestyle.
You start a just a depressed young brother just dropped outta school and you have to try to build a life for yourself. Start small time crimes, like scoring cheap drugs and reselling them, get a few friends and start your own gang. This will have a full customization suite to it, including gang colors, "attitude", and tags.
Combat is short and intense, a single bullet can end you and street brawls with melee weapons is usually dependent on who swings first. Will include a wide swath of weapons, from cheap .22s up towards highly illegal assault weapons. Armor can save your life, but if you gain a reputation for wearing it, your enemies will begin to use different weapons to get around it, such as explosives or a very sneaky knife attack.
Doing your crimes is kinda easy at first, as you're so small time the other gangs and the police might not notice you. The more you do it on a gangs turf, the higher a chance they'll notice you. If they do, you could bribe them and gain their protection, but they'll still leave you in the dust if you arouse police suspicion. But once you start gaining rep, it gets harder, and the cops will harass you if you fly your gang colors and stuff.
CK2 levels of intrigue happen as you gain a reputation and some of your homies might not be as loyal as you think. The gang management will be a bit automated, in that you initially recruit individual members, but over time true management requires leveling a few homies to shot-caller level and assign new members to them and order them toward certain goals. Defending your turf, buying/making and selling drugs or weapons, endorsing a pimp and having him run a stable of hos or recruiting new members from disenfranchised youths.
Getting caught by the one-time puts the game into a sort of DF-like world generation as the world goes on without you; if your gang was well-structured and diversified enough to survive with the increased police scrutiny while you're away that once you get released you can simply pick up where you left off if your rep was high enough. Or you have to start all over again.
Overall, it'd be a pretty damn depressing game; if you die your gang continues on without you, and you even get a funeral cut-scene that reflects how well you did. And then you can create a new character, and maybe join your old gang. Or make a new one and fight the old one.