This is my favorite build, made on a flattened Nicomedia with extra exports. I usually stop trying to create a standardized build part way through and just screw around, but this time I made it to radial symmetry. I'm sure some fine tuning and beautification would help--there's room in the corners for markets/tax/prefects to join in on the symmetry. Buildings with a service range and houses are what's symmetrical. Reservoirs were being sassy and having inconsistent ranges, so they break symmetry. The temples repeat for proper coverage--the gods aren't symmetrical but that's not super important. The equite domus on the northwest and southeast sides next to the reservoirs that were inconsistent can be replaced due to unemployment. Culture is 97 from the 4th temple from the middle on each side being mothballed to help get Bacchus's benevolence and max out all 66 mansions.
If anyone looks at this and sees what's up with those reservoirs, let me know. Or let me know if I'm crazy or made a mistake. I'm pretty sure it was the exact same build rotated and I had to delete a road to get the reservoir to reach the patricians.
If I rework this, I think I'd like it with temples in the center, arenas on the diagonals and coliseums on the straight ends behind theatres. That image of a circle of arenas/coliseums sounds cool. Working in a governor's estate and basilica with duplicate temples and libraries surrounding them would look great and easily have enough desirability for grand mansions.