Michigan, as you mention, has a really creepy governor (more automaton than Captain Evil) and a batshit crazy, Tea Party-ish Republican legislature. The Superintendent is not--unlike most states--selected by the governor. S/he is chosen by an elected State Board of Education.
Earlier this week, a team of some 30 Republicans crafted a resolution to dismiss the (duly and democratically elected) State Board and the Superintendent--and replace all of them with a CEO, chosen by the Governor. Of course, this would require a change in the constitution, so they're putting that on their to-do list, but they made a really big deal about it. It's their goal. Soon.
The Superintendent was a kind of compromise choice, made by the (mostly Democratic) State Board. There were other (better) candidates, but Brian Whiston was chosen, largely because the Legislature loathes the State Board--and he had built relationships with legislators, when he was a lobbyist. That's right, they picked him *because* he was a lobbyist, and an actual public school superintendent, in a majority-Muslim district.
He actually does know some things about running a school district. The piece you were referring to (start testing earlier!--test more often!) drew lots and lots of scorn, but it was mostly about dumping the MI version of the SBAC/CCSS test, and replacing it with MAP testing in the fall, to address something teachers have been asking for: early feedback on kids.
Personally, I think it's a crappy idea, but I think it's the Supe's way of trying to make nice with the legislature, let them know he's not going to let go of accountability, even though he's recommending dumping the high-stakes test we most recently had.
Furthermore--he's not really in control. The legislature doesn't want a Superintendent or Board. They want to completely trash MI ed funding and firewalls between public and private. They want to "unbundle" the public system. The Superintendent was hoping to give them an idea that would fly, and keep channels of communication open between the Board and the Statehouse.
Brian Whiston is not the worst Superintendent we've ever had, by a long chalk. In fact, he hasn't been in place terribly long, and had a personal tragedy early in his term, so we haven't heard much from him. I would rather have him than someone appointed by Governor Endless Stare.
Sad thing--MI used to be a flagship union state, with excellent public schools and universities.
So maybe Whiston is trying to navigate through a tough place and getting stuck with some crappy choices. We'll see what happens next.