Mass Effect crossed with Total War.
It would be incredible.
The Milky Way as the battle ground. Hundreds of solar systems to travel to and conquer, enslave, or destroy. Within the solar systems 5-20 planets? Within each planet, Continents, nations, factions, whatever.
Multiple races, species, governments, militant groups.
I don't know. When I play Empire:TW, I can't stop thinking about how amazing it would be to travel from Earth to another system and start an interstellar war.
...................You know you'd love it...........I'd never stop playing it.