Cities= mini-Civs
Merge the Politics and Diplomacy, so that your government/Empire is always about negotiating a relationship with your people (cities) Fortunately, They cannot win the game, so they don't have to think in 'gameplay competitive terms' like the AI Civs should.
The game can start up with Lots of these cities already founded
Territories and Changing Scale
When the game starts, a Tile is ~1/256 of the size it is normally, as time passes, tiles merge. Cities are collections of tiles and Buildings that are all connected enough collected, so they can also Merge. Your entire early empire may end up being your late game Capital City
Range instead of Speed
Units need support, and not just money, on the other hand it shouldn't take 50 years to cross your empire. So give units the ability to defend, and attack, an Area, rather than a single tile. Or the ability to conduct scouting missions (out to a certain Range of tiles Away from your empire) [like air missions these would have a Chance of success, the longer the range, the more chance they may get intercepted and killed before bringing back Any information]