By any chance have you read the one man/one vote decision of the United States Supreme Court promulgated post 1963?
If a Board of Supervisors who takes a member from each organized township is unconstitutional, why do more than 20 other States still have them?
It would appear that no one asked the people of the State of Michigan what they wanted, by mandate of the people. Read Norton v Shelby Norton v. Shelby County, 118 U. S. 425, 442, 6 Sup. Ct. 1121, 1125 (1886). “An unconstitutional act is not a law; it confers no rights; it imposes no duties; it affords no protection; it creates no office; it is, in legal contemplation, as inoperative as though it had never been passed”
I would have never been suspect of this form of county government until the States progressives began to eliminate our local Township government altogether! The Progressives wanted to eliminate townships in 1908, but, lost by a single vote!