It would be nice to be able to rescind an alliance request to another player. Currently, if I offer an Alliance to Player 'A', they can choose not to accept or deny my request, leaving it in a limbo state. The problem with this is when you are playing with fog of war enabled, Player 'A' now has an ability to look at my entire map at any point during the game by accepting, then quickly canceling my request. It can be done so quickly that often you dont get a good look at their territories making it a somewhat uneven exchange.
I propose you have the ability to rescind an offer whenever you like, or that offers expire after one round.