Would it be possible to have some global control of the displacement subdivisions.
Why? Let's say I had 10 materials all set with different values between 3 and 6, and I wanted to turn them all down to 0 quickly, I'd need to adjust each material.
If we had a global (kernel?) multiplier, I could just set that to 0 for "preview" purposes, so the scene would be fast to work with, then set it back to 1 when I wanted to render final HQ displacement.