Pretty simple idea. Have a system where you can mix and match Perks on ghost shells as long as you have unlocked the perks you want to switch out. I have the +10% XP boost moon shell, but not the Eris one. I really like the look of the Sagira shell, however it doesn't have that perk. I would like to be able to replace one of the perks of Sagira's shell with the +10 % XP boost from the Moon Shell. Now this would only be for ghosts. Please think about it, Bungie.