I think this would just move people back to trade secrets.

That said, I think patents could be given out less often when the operation of the device is clear or can easily be discovered by the public without a patent.

E-Ink screens released without a patent kept under 'trade secret' wouldn't have mattered, the idea would have been implemented elsewhere.

I suppose you could argue that without exclusive rights the original inventor wouldn't have bothered to create it at all - in that case there's probably a better middle ground of something less than 20yrs. 5yrs? 2yrs? First $1million in profit?