Saw you there in the game, and understand your frustration. But there has to be some rules, that apply to everyone. Then it could be discussed how they should apply.
I would agree that change of home city, should only be done once (maybe twice) during a round, and only until a certain time of the game. For instance once allowed in era 1, and one more until start of era 6 (when regions decided end game city)
As for changing your region, even if it was allowed once during the first era, I think it would be exploited too much. Many would then agree beforehand that everyone changes to a given region, and that region would have all the best players.