I'm hoping they add new game+ to this as well as adding another ability slot and more skills to your character.

I know they can't exactly go back and change this now and I don't know if they could even get him back on the game, but I wish they made it an option to
Spoiler:  Show
join Walker as an optional path to take in the game instead of being forced to kill him at the end.

Make it so now (because we have AI teammates) we can go over to Golem Island without 3 other players and instead go over with the AI team.

Make a walker skin to buy (with in-game currency) and play with without the mask and cloak on. (like what he wears for most of the game anyways)

Make the AI team members stop freezing while following you and wind up teleporting everywhere until they finally fix themselves or by having to turn them off and back on again.

Add more civilian looking clothes for us to wear to Erewhon.

Allow us to finally be able to holster our weapons while out.