I would like to see an option added where players can share their stats when they win single player games. There could be a community billboard or something, with the player's name, the level name, and a score, turns, armies, etc
Muli (iirc) already made http://communitylevels.online/ui/
, that has pretty much all functions you asked for.
Misread title and thought u were wanting an official coop mode
You can do co-op in MP when you just make all your opponents AI's
Co-operative. Multiple humans working together to defeat 1 or more AI's