Of course Rome is interesting! Stellaris will be a flop if it is indeed a space game.
I mean, Rome the city is interesting. Rome the empire and its ugly sister, Rome the republic, just didn't do much of interest. "Oh look you painted the map, yawn." I do that all the time in games already with interesting countries, like the Ottomans.
An Ottoman game would be cool and interesting, sure. They're like a more successful and interesting Roman Empire.