Waaaay to much text. Plus there are several different ways you could go with this flag. Michigan has a rich history from which one could draw, but they chose the same tired formula as 20 other states.
My first thought was cars. Detroit is the Motor City, Henry Ford built his factories there, America learned to drive in cars made in Michigan (figuratively at least, my first car was made on Honshu). Of course, that could be tricky to pull off. If a car was used as the central emblem, which car do you pick? The Model-T is the most famous of the early models, but then there is the concern that GM wouldn't be happy flying a flag with a Ford on it. That argument could be made against almost any model made in Michigan. Heck, even just a simple stylized steering wheel would probably draw criticism for looking too much like the Mercedes logo. So the automobile is a non-starter.
I suppose one could just put the Red Wings symbol on piece of white cloth, but you'd probably run into copyright problems. I'd bet it would be popular though.
As a jumping off point, I'll be using the flag of Detroit, mainly because it is one of those city flags that just looks really good:
At first glance, this flag seems pretty busy, but so does Maryland's and that is one of my favorites. Ignoring the seal for a moment, the flag recalls the USA, France, and England, while sticking to (fairly, the lions could use some work) simple symbols and only four colors. Even the seal is not bad compared to many others out there. I mean, how many people would put a representation of their city burning on the seal? Apparently, Detroit did. With a little cleaning up, this flag could easily serve the entire state.
One other issue to keep in mind is the differences between the two peninsula's of Michigan. Though containing only a small portion of the state's population (roughly 1/30th) it is integral to the identity of the state. Luckily, this flag provided a way to represent them both:
Admittedly, I didn't do a whole lot to this flag, just removed the text and the background. I kept the two ladies though to symbolize the two peninsulas. The flag looks good with that circle blank, but I decided to hang on to them. One could even claim that their arms are touching to reference the Mackinaw Bridge. I won't do that, because it's kind of a stretch, but someone else could. No matter what is in the center though, this is a far more striking and recognizable flag for Michigan than their current model. Maybe it's time to trade that one in for one with power windows. . . Ok, I'm done stretching that metaphor now.