If you want to encourage businesses to locate in Michigan, make it easy for them to pay their taxes. We should scrap the entire MBT structure. It is complex, attempts to combine a corporate income tax and a european style value-added tax, with the worst of both worlds as a result.
Keep it simple. Make it easy for companies to pay what you want them to. Take federal taxable income, make the couple of adjustments that are required (tax-exempt income, etc), and apply a rate. That's your tax. Include by reference federal law as currently enacted, and you are done. Don't include any credits or special treatments. They only mess-up calculations and try to pick winners & losers in the state. If you want economic diversity, just have this base without any special carve-outs.
The lower the rate, the better. At the very least, take your expected corporate tax payments and divide by last year's business income in aggregate. That will give you a neutral tax rate.
Do this and you can reduce your Treasury staff, your state auditor staff, clean up collections, and make it much more attractive to do business here. You can save legislative time wasted confusing the tax code and focus on where to spend that money, or hopefully, where you can cut spending.