Look at MR.Tenchu rip off up here. I'm still waiting for this new Ninja game that should be like Assassins Creed, but is Tenchu.
Anyways, I had an idea for an OS-FPSRPG (Over the Shoulder First Person Shooter Role Playing game, much like Fallout, but with a better physics engine where you blast enemies off true fee with a shotgun no matter what because there is no way anyone would be standing after point blank buck shot into the chest. It would be multiplayer up to 24 players per server in a pretty big open world city with a market, black market, mercenary jobs, deathmatch with classes varying from heavy weight to light weight. Heavies would get ordinance support, but are less mobile, while the light classe could sprint faster and more agile and can access more of the rooftops of buildings through a grappling hook feature whereas the heavies would need to find stairs or call in air support onto the roof or simply get other lightweigt teammates to erradicate the roof top dweller. The heavier units would have more health an would begin with body armor as part of their class.
The vehicles
Drones that hang out and follow the Heavy Units or camera drones for all classes that will allow you to go Over the Shoulder or Third person and let you peek around corners without revealing yourself just an advantage over people in FPS. Or small airdrones that seek an destroy roof top dwellers, but are quite small compared to the Heavy Drone. Convoy jeeps, Armored Trucks and more.
The controls would allow you to sprint, jump, sprint-jump, sprint-slide climb obstacles, slide or dive into cover, peek out of cover in FIrst Person unless you have an OS drone (over the shoulder) and it can be shot