Idk, I saw the Killer Instinct character model and imagined a new game as some kind of modified/innovative Gears formula - like, take a cover-based shooter, make it a little more like a brawler, like 60-40/70-30, and add verticality to the mechanics and level design somehow - like, you can hop up to higher platforms for cover and jump back down, dive underwater for cover, or swim and pop up elsewhere in the room.. or hop and stick to the walls temporarily, something.. Easier vaguely imagined than done, but given the aesthetic and the need to do something fresh and big with a 2d property in 3d space..
The other 3d transition possibility for 2d brawler/sidescroller games - I thought this could work for Final Fight - is an open-world or semi-open (Gears 5) game where you navigate a 3d world (say, the streets and alleys of Metro City, for FF) w/ some adjacent roleplaying, puzzle-solving conversation tasks (think LA Noire, or The Wolf Among Us) that work thematically, and then adjacent to the space are enemies who confront you, or bait you, sucker you in, etc. - at which point the plane shifts to a 2D fighting game , maybe different enemies shuffle in and out of the action, tag team style..or - Def Jam: Fight for NY would be maybe a better model..