I too have been thinking of a cool mode:
Straight from AoE2, all the MCVs start in a random position around the map, if doable, where they can move and choose the best position to deploy.
Alternatively: the MCVs can all start inside a naval transport surrounding an Island in the same or nearby position that move to the main island or surrounding small islands to deploy.
I realised that there would be a need for many types of Islands or Random Islands for this to be possible, but even without random islands, this proposed mode would be ideal for those who get bored of the basic same map/same game every time and allows people to try and rush each other by deploying near each other or take weird positions on the map that might lead to a greater advantage later in the game.
EDIT: This could also be a huge singular multiplayer map