I kinda have an idea like this, using world war 2 as an example.
A player would be elected to command each side through the rts mode. He would have access to support abilities, like artillery air strikes, and supply drops. All of which cost resourses.
Players would be able to create the look of there characters, and choose weapons. When a battle happens, all players are in the game.
One style of a map would be Assault. The defenders just hold the town, while the attackers must capture the town with-in a time limit. The defenders spawn in buildings, while attacker come in waves. Attackers have unlimited resourse, while defenders gain resourses from holding houses, and stopping waves.
Now the commander would put markers on what he wanted completed, and players would recieve points, to spend on weapons and abilities, for completing these orders, and lose points for not completing them.
I hadn't gotten farther than that, but I think that covers a FPS, RPG, and a RTS.
"Our destination may define us, but it's what we do along the way that makes us who we are."
-MTS
