[Moriarty]

Basically a ladder system works by initially seeding into a rough order, probably by level.

Usually you challenge a player up to 3 places above you, if you win you move above them, if not you move down a place.

To simplify it for AL you could fight anyone above you and if you win then you move above them, if you lose you stay where you are, that way after a couple of weeks of people fighting back and forth you would get a basic ladder in almost power level order give or take some randomness which would give players incentive to fight and climb the league.

To move above your own gang members youd have to wait for a GCD or leave and risk losing your gang bonuses

We seem to be lacking a goal around here at the moment, I believe this might help to add one.