A atmospheric viking themed game with a space pilot stranded behind enemy lines. Has to struggle with the psychosis of his titan, and fight off waves of crazy viking warriors. Solving puzzles to gain access to Hel and shoot her tits off. I'd dig that.
This is easy for me. The Division is a shooter/RPG that was released as a shooter/rpg and has been slowly patching out as many RPG elements as possible in it's quest to eventually become a pure shooter.
You would combine them by mandating that they stop removing the RPG stuff and put back in the things that got removed because the shooter fans got upset that someone had made a build and was using RPG stuff and systems to find success rather than just strict COD/Battlefield gunplay and nothing else.
As an Inkling you partner up with an Octarian and fight your way through a Salmonid infested Shibuya. You play with Motion control and d-pad to control both characters simultaneously. Surprises and twists abound.
Shadow of Mordor and Rampage: Total Destruction. Talion eating people and destroying cities worldwide? Rampage monsters destroying shit and eating Uruks in Mordor? It's an interesting mix.
Agents of Mayhem and Slime Rancher. So a single player open world hero shooter emphasizing exploration and featuring The ability to make amalgamations of the heroes. That actually sounds promising.