Being able to add custom panorama background and use it. Since Lunar Client has already implemented a theme changer between 4 themes, I think they should add a 5th and say "Custom" or something like that, to be able to use the texture pack's panorama. It will add a lot of customizability that was removed along side the patch of the Custom Lunar Client themes a few months ago.
#Add custom panaromas
rancid raven