Clothes and character customization.
New DLC has a party of space-suit wearing clones as a promotion video and it looks quite ridiculous (who would want to use a pool in a spacesuit?).
There should be some basic character customization and alternative clothing. Doesn't need to be full-blown RPG face editor, just a bunch of preset faces, a few clothing sets that are not space suit (meaning no jetpack/oxygen), and those should be equippable within world as items, and not through game-wide character customization.