Open world game where you play as a robot trying to upgrade itself to 'perfection.' What that means would be up to you. Maybe you want to blend in with humans perfectly. Maybe you want to become a walking (or rolling) indestructible weapons platform and take over the world. Maybe you want to split the difference and be a superhero.
I figure it'd work best as one of those exploratory games where combat is optional. But there would also have to be an insane amount of detail and flexibility for it to be up to what something like that should be so I'm not exactly holding my breath.