How about improve new ways to the victory?
Middle age was such a creative time. Intrigues, espionage, trade and faith. A strong point in AoE is always been the role that has the military for the victory but it could be also a weakness after all these years. Of course, I love the dynamic of the game otherwise I would play another game but it would be cool to insert new things on the cake.
Game always pushes you quickly through the time to create as many soldiers as you can impeding you to really enjoy the city and what you are doing to get there.