Better light and rendering tools
The lights in Substance Designer are very poor. You can only activate two, and you can only move one light (never the other, which is stuck in place even if you activate it). The one light you can move is very awkward and difficult to move already.
I would like to have rendering tools built into Substance Designer that are absolutely worthy of being in the best material authoring software. movable, rotatable spotlights and point lights, among other things, would be very convenient and professional.
At least shadows in Open GL view.