It would be a big improvement if Larian (or modders) could just add colorization options like the "dye" options for Geralt's armor sets in The Witcher 3. That was nicely integrated into the game. You didn't immediately get color choices, you had to find the various dye colors in the world or buy from merchants.
I could then make my Rogue's leather armor black instead of brown as a bit of user customization. It might not be as useful for the metal armor sets, but great for leather and wizard robes. And it wouldn't require completely new designs, just a change in the color palette.