A system already exists in the game for loading in custom textures, so custom maps can be run. So why not weapon and player skins?
You can import a custom skin or pattern that only shows when you’re on your ship, but can be added to a workshop that works similarly to TF2’s or Guns of Icarus’ workshop: where community items are voted on and if they receive enough votes are added into the game and become part of the selection of skins and patterns. Skins could also be made gun or character-specific, with normalmap support for players to completely change the look of a weapon or character just by modifying textures - a brilliant example being this CSGO gun skin that makes the Mag 10 appear to have a new model, but is just an optical illusion
And to prevent the tone of the game being ruined by someone running around with a shiny pizza-patterned SMG there could be an option similar to Combat Evolved on the MCC which allows you to turn off the ability to see community-made weapon skins, preventing your experience from being visually ruined.
It helps build a community when players feel like they can vote their community member’s artwork into the game and decorate themselves with it, or permanently memorialize in-jokes and memes and have some sort of impact on the game itself.
A steam workshop means the team doesn’t have to create their own custom website or spend lots of time looking at private submissions via emails. It also of course always goes past them so if a skin is deemed unsuitable or artstyle-breaking it doesn’t have to be added