By way of their latest weekly update, Bungie have revealed that they are currently working on revamping the user interface for Halo 3 to make customizing the game easier.
Our UI has come on in leaps and bounds. For a long time the UI development was happening separately from the actual game, so missions and other options would be chosen from a debug menu. Now the UI has been rolled into the game, so you can use it like a regular game interface for most things, and see it develop along with the rest of the game.
As it stands now, the interface is designed to make it very simple to get to a "lobby" and make all necessary changes from there - so that you can customize your experience, appearance, and more importantly, really specific game types from anywhere.
Folks who've played a lot of custom games know that it is very frustrating when the "Quick Options" selection just isn't enough to get all the options you want in a game type. You won't have to worry about that from now on. And you can also change your controller setting from anywhere, at any time. That one was a given, right?
You can read more about what Bungie are up to here.