The ability to save outfits would be nice. Having to manually switch every piece of my outfit when I want to pick my other look gets tedious fast, and I think it would benefit sea of thieves greatly anyways due to the insane amount of clothing and equipment available. Being able to save my currently worn equipment, clothing and vanity to an outfit slot would be very nice.
For example, I have two outfits I frequently wear.
A red one, with parrot equipment and a black one with ashen equipment. Being able to save both these outfits and equipment sets and quickly load them would be very useful I feel.