A multiplayer 16 vs 16 (or more) mode where each side gets their own Mammoth.
The object is to disable the other team's Mammoth. This could be accomplished in a variety of ways, perhaps by boarding it and destroying parts of it, or your mammoth has a main gun that can be fired when certain conditions are met, etc.
But basically, I want Mammoth vs Mammoth combat. Am I asking for too much? --- "If the day does not require an AK, it is good." The Great Warrior Poet, Ice Cube