Note: The Intel 31.0.101.4577 driver only actually supports UHD 7XX and above. Should I be trying to track down the last supported driver for each of the previous GPU generations or is it fine to just pretend that we have a 101.4577 driver that supports HD4000+?
I can only guess—and I invite the older and more experienced Direct3D developers to chime in here—but it does sound like a lot of work for something unlikely to matter.
Ideally we would, and that's the main purpose of the wined3d_display_driver enumeration. Chances do seem pretty good that we could get away with just reporting the new drivers for the older hardware though...