HI !
First, all apologize for my bad english langage !
I see that sometime it's not possible to take back our move (expect quit the game and rejoin), why don't add a cancell key, a way for someone to cancel the last move he did but he don't like during his turn.
I also appreciate if when I play with alliance, a teammate can stack unit on my city (with mine) to protect the city against the other player.
I hope you can understand my mind !