It would be awesome if they put some COD factors into Halo, like going prone, aiming down the sights, and some weapon customization. As a matter of fact, put a program in there that lets us forge our own weapons! it would also be cool if we could duck behind cover and fire from behind it.
Let us choose from multiple Species to play as like Elites, Brutes, Spartans, and Forerunners (if they are in the game, of course)