I know there was another thread about it, search function, yada yada, but I'm making a fresh one anyhow:
so, one of the gameplay styles I think would translate extremely well would be phantom from supcom.
heres how it goes: there is one or two people (depending on the number of people participating) who is the "phantom", the "phantom" has double resource production (and other such advantages) that cause him/er to be quite powerful, as a drawback the game is practically a 1vall, thing is that nobody knows who the phantom is...
so essentially its a massive espionage game where you win by fooling everyone (if your the "phantom") or by sniffing out the phantom
the only real thing that would get in the way here would be sharing of intelligence data, one could easily use that to predict how much you're making, and if thats more than you should be.
one of the keys to this would be having one unit (homeworld/flagship)of which you need to kill in order to reveal whether that player is innocent or phantom (and kill him in the process) this would make the gameplay much quicker and faster than simply stomping the enemy out.