I have that idea since 29. Jún 2010 when I saw trailer I was guessing what will be story about... Story in Chaotic city San Paro. Campaign could be like NFS rivals when you play alternately once as male enforcer once as female criminal (enforcer protagonist could be like some rough cowboy "Benjamin McCall from Call of Juarez Cartel" but younger) (criminal protagonist could be like Harley Quinn but bloody redhead to fit criminal colors)
Both maps could be connected Waterfront and Financial and all customization computers from social district could be in one big map specific in shops for example ( clothes customization-in clothes shops,car customization-in some garages... around whole map) + adding motorcycles specific sport bikes for some gangs (like saints row Ronin gang) or police bikes for enforcers
Story: Enforcer character start like trainnig detective he could have some problems with self control like solve problems more violent than he should normal so he get new partnes to control him (coop or singleplayer bots) through game he gets more calm try using head instead violence (character development)
Criminal character start like some greenhorn in organized crime more like scary but through campaign get more brave with partners (coop or singleplayer bots)
Prolog: criminals robbing bank in team they have new greenhorn female character. Enforcers are sent to stop them. Criminals and enforcers get in shootout while enf. protagonist chasing crim. protagonist in alleys. Crim. protagonist hide behind trash can. And while enforcers shooting on criminals enf. protagonist see crim. protagonist duck and scary. (he think about what boss said care more about people not about goal to kill all enemies) he run to crim. protagonist and mistake her for civilian so he will be actually protecting his enemy. When shootout is over he check if she is hurt ask her for name she tell him real name give her his visit card with his real name and let her go. She get back to criminal HQ while he get back to Enforcer HQ.
(Whole story could be about crossing their paths and climbing their ranks in each fraction) but he cant know who she actually is same as she cant know him. They change their appereance enf. character infiltrate criminals like undercover cop and crim. character infiltrate enforcers like new enf. support member
They work together while one protagonist trying success in fraction other character trying to undercover sabotage whole organization from inside (for example criminals are sent for some plans in briefcase when they collect them and let them in car for boss enf. character collect intel for enforcers or do some spy missions with antenas...)
Through story characters get closer in their relationship have some romance but still dont know who they actually are wearing mask diffrent clothes.
At the end when both sides collapsing Enforcers and Criminals player get last mission and that is to sacrifice one protagonist and destroy totally other HQ
Both endings could be similiar for example last mission Enf. character take whole enf. team and attack Crim. HQ in last big battle
ENF-Ending: When he shoot his path to Crim. Boss they point guns at their self and while talking Crim.female character appears in room (undercover) as Crim.Boss Right hand. Only Boss call her by her real name so Enforcer character realize who she really is. Boss trying to kill enf. character but female character jump in front of him and he deadly wound her. While she dying in enf. hands boss escaping. Protagonist gets furious and chase him he is decided to kill him while his partners are behind him to stop it. (You can kill Crim. Boss and end up in prison for disobey arrest order - Bad ending.... or let partners arrested him Good ending)
CRIM-Ending: When she shoot her path to Enf. Boss they point guns at their self and while talking Enf.male character appears in room (undercover) as Enf.Boss Right hand. Boss call him by his real name she realize who he really is. When Enf.Boss try to kill her as most dangerous criminal in organization male character jump in front of her and get deadly wounded. While he dying in her hand Enf. Boss escaping. She get furious and chase him she is decided to kill him while her partners are behind her to help. (You can kill Enf. Boss to controll whole city and later get killed by your own members cuz they want city for their self - Bad ending.... or you can walk away let your gang members kill Enf.Boss and left that life - Good ending)
Criminal character idea: https://ibb.co/xS4LYX2
Enforcer character idea: https://ibb.co/GPvNhbr (that mustache add him more rough gunslinger-bounty hunter look)
Of course players can cuztomize them but that could be their basic look
(All things that player win and receive in multiplayer get stored in singleplayer so people will be more willing play online to get more content in story singleplayer) - sometime especially in late hours servers are empty and you dont have anyone to play with so you could switch to singleplayer and play story