its just not something that was ever going to happen
the story is centered around the world being in sort of a stalemate/slow grind of the fire nation victory if not for the intervention of the avatar so nothing really important can happen that isn't centered around basically the events of the show
on top of that they wussed out of allowing aang to kill the fire lord in order to keep it on the lower end of PG which indirectly limits how far you can really go with other material you make later
and it will be a cold day in hell when the corporations that hold the IP and the gigantic homosexuals in the creative departments those corporations have at their disposal make a game that isn't horrible dogshit

anyway I'd hold azula in a tight embrace and give her a big smooch as we lead the nation to conquer everyone else in the setting