I would vote for Trump in the GOP primary if the primary were held today. I confess to being something of a RINO, but I'm still a Republican primary voter, and I am a social conservative.
I, too, would be stunned if Trump were the nominee. I can't say I'd be disappointed, because the political establishment has provided the kind of free trade policies that caused the loss of manufacturing jobs in Michigan. (My wife is from Michigan and I'm from New York, so we know about disappearing manufacturing jobs.) Yes, we can bad-mouth unions, but it was the greed of the investor class, coupled with free trade agreements that took jobs that the Southern states stole from Michigan and New York and shipped to Mexico and China, courtesy of NAFTA and GATT. And the bulk of the GOP candidates were OK with this.
You're a local party chair. So you must see how the national GOP, over time, gave its corporate donors everything they wanted in exchange for rivers of campaign cash. Part of that the corporate donors wanted was free trade so they could export jobs (which they did, and do). You've seen what Pat Buchanan observed; the GOP gave their corporate donors everything they wanted, and they got the campaign cash, but it cost them the voters that gave them their landslides. They lost Middle America for the GOP. They lost Michigan, Wisconsin, Iowa, Illinois, and the industrial Midwest.
You probably know that you can't win elections in Michigan without getting the votes of at least SOME unionized workers, and not just the ones that go to church. Trump is talking to THOSE people, people who once delivered Michigan to the GOP 5 Presidential elections in a row. They left in 1992 and they aren't back. Some have died, but the younger ones like them aren't back, either. Trump has the gumption to let these people know that their own party has screwed them. As a registered Republican, I would like to know where the grass roots pushback is against free trade, which has ruined Michigan.
I'm from a union family. I don't support those trade agreements. If you took a poll of the grassroots in my party, you'd find a lot more opposition to those that people would think (not a majority, but significant minority).
That also said, the unions haven't done a damn thing for us in 25 years when they sold us out to back their democrat corporate masters (you read that correctly). Clinton signed NAFTA and GATT. The union leadership continued to back them to go to the correct cocktail parties. They sold out on outsourcing contract time as well. Unions became about politics instead of contracts. A lot of us with ties to non government unions know that.
These days, the big union strength in Michigan are as much about government unions instead of auto unions. The MEA is the big one these days. A lot of people gave up on trade. I couldn't vote when NAFTA was signed. Granholm also hurt the democrats here as much as the two President Bushes (W's second term esp, along with his dad) hurt the Republicans here.
I agree there's openings for a "jobs" candidate in the Midwest. A lot of things have changed, but Michigan is still a pocketbook state first that is center-left economically and center-right socially. The "do ones job" issues matter the most. I think Kasich may be the most electable candidate here. I wouldn't bet against Walker either.