There are a lot of avatars trainer out there... I don't see much that this one could offer that is different enough to be worth a subscription to the dev's Patreon, for example (if he has one or if he intends to open one).
Now, one thing none of those do is one with a female protag, for example.
Why not put Korra in Aang's place or let the player choose between them? Yes, a female avatar, without futa, "bending" Katara, Toph, Azula and others... that would be different and worth following the game.