I personally don't like the idea of being able to just go to MainMenuState whenever, cuz you can easily add this to your mod, and if you really are stuck in a ModState or in a state you can't exit, its really easy to leave its literally this:

function update(elapsed:Float) {
 if (controls.BACK) FlxG.switchState(new MainMenuState());
}

super easy.

I agree with Mouse Controls being in CNE, but most mods override the menu. I don't see the point in adding it anyways.

if you really are stuck in a ModState or in a state you can't exit, its really easy to leave its literally this:

Have personally encountered a situation where a modstate improperly loaded and it made me unable to escape without restarting the game entirely. That is the entire reason I added this actually. I personaly think having a "oh shit I need to go to the main menu quickly" button bound to something you're not likely to press on accident is better than not having one at all