As a Roblox developer, it is currently too hard to create custom viewports with universal lighting by having to replicate the lighting through each viewport. We can solve this issue by have a toggle in studio that uses the same lighting as the main viewport. It would look something like this in properties: 
What can I do with this feature?
You will be able to display separate models and items through different frames with the same lighting as the main lighting similar to what CS:GO does here:
(This is the viewmodel, on a completely different layer than the background)
This will improve not only my experience but many other developers because it will open up a new lane for creativity in your game. Many FPS games will be able to utilize this so guns and models won’t be clipping which could affect not only the user experience but competitive gameplay.