onedreamer
Dragon
Of course.
Number of cities - Well the Roman Empire needs to have lots of cities, can't do much about that.
true but this causes instability, heh. All Empires (including the Roman one) collapsed when they overexpanded.
Civics - Never less than 3 stars.
Civics, not civics stability. Civics you adopt influence the stability of pretty much all categories, including expansion.
Look if you haven't read my posts before I've tested it out; when I gift 2 or 3 cites on my border to other civs my expansion and overall stability immediately go up without doing anything else. I understand that other factors are involved but it seems to me like this is the predominant factor as "combat results" for instance should be overwhelmingly in my favor.
No need to get all set up, I was trying to help as it seemed you were looking for clues on how to improve expansion stability, but since you already know everything there's no need for it.