It would be absolutely useless as, IIRC, debug firmware relies on hardware that isn't present in retail Vita's, it most likely wouldn't load at all unless it was heavily modified somehow to do so.
IDU mode is about as close as we can get right now, which adds in some neato functionality and allows us to run the Package Installer again. Voxel has a thread about IDU mode here if you want to see what it all does:
https://gbatemp.net/threads/ps-vita-idu-mode-everything-you-need-to-know.438482/