What is a video game that you'd love to play, but no one has developed yet?

A singleplayer open-world sandbox RPG in the vein of Skyrim, but you have powerful abilities on cooldowns like in MOBAs/Overwatch, command troops like in Mount & Blade/Blood of Steel/Conqueror's Blade, and can go around conquering cities/developing your own nation culturally/socially/technologically/economically/etc. like Civilization but more open-ended where you can do things like decide actual religious doctrine and encourage specific aesthetics/music/social norms.

Obviously, though, such a game is incredibly ambitious and I don't think it'll ever be made, as it takes the most unique and hardest-to-make parts of several other games and then combines them. Still, I'd love to play it.