I have problem with the claim 'negative feedback principle'. A principal is a very general thing. I'm not a HS Black scholar but I believe that Black was referring to electronic controls. Its unfair to those who may wish to nominate negative feedback in process controls, PID, Foxboro Company, combustion controls, generator voltage regulations, load control, and so on.
My second comment is a general one. Has the proposer looked at all of the previously awarded milestones to see if this proposal is in any way in conflict with previously stated claims?
I also concur with Mischa Schwartz's observation. In this case having a multiple plaque presentation is logical. But I also agree that removing redundant text should be considered. Finally, a check if a similar milestone, (like in the case of the transistor,) exists to remove conflicts, may be in order as suggested by Ggcooke.