I gurentee new maps will come. Possibly Hang em HighBut. Alot of people have said the mongoose(ATV), flamethrower, and fuel rod will be addition to multiplayer. I really want them but it could be a rumor. Possibly new gametypes. Others have mentioned new multiplayer models like, arbiter, marines, brutes, flood, hunters, and even...grunts! About 1 out of 6 players on live use the elite model, I use elite which i like, but i understand when you cant refuse the Spartans visorhttp://img.photobucket.com/albums/v307/catguykyou/bungie.jpg
There are already several threads about downloadable content, post in those.