Give developers the access to UV data as so that they can achieve current industry standard visuals, effects and feedback to systems.
This would allow for developers to create functions that control the behaviour of UV scrolling techniques for things like VFX and alternative color data on custom meshes.
Multiple UV channels would also be awesome if UV channel 2 automatically applied a multiply blend effect over UV layer 1 so areas of geometry could be tinted using a combination of a bespoke grayscale diffuse map and a selection of color swatches on UV layer 2.
Cheers!