They need a game like San Andreas but more city orientated, maybe set in Tokyo and have it about the Yakuza, Triads and other foreign gangs etc. Set in a huge map like San Andreas with the freedom of San Andreas, graphics of GTA IV. More weapons, more mini games, more vehicles, skill sets and fighting styles as well as making the character totally customisable and side missions maybe extra content on them, possibly multiple characters to play different stories etc.
An online co-op story mode would be good where each character plays a different role or even a MMO where you can choose your job set like cop, army, paramedic, gangster, taxi driver, hooker etc. each with their own skill sets, perks, fighting styles, weapon styles and jobs that earn money to upgrade stuff. Not just running around killing eachother but being part of a huge city with hundreds of people. Not like second life I mean having more interaction but having your own agenda and storyline within the game like being a taxi driver to get thugs to a bank to rob it and having the police chasing you etc and all being people rather than bots.