So, basically, most opposition to Trump comes from the political correctness side of things. I, however, have a different view on him.
His Tax Plan Would Increase Taxes On Middle Class Families
According to a Bloomberg report, Trump's tax plan would give major cuts for upper class individuals ($250,000+), but would increase the taxes on a majority of people within the $250,000 - $45,000 bracket, the largest portion of American families today. While I don't necessarily believe in class-based tax rates, of all the classes, we need to preserve the well-being of the middle-class, and a tax hike will push more and more people into poverty.
He, And Especially His Running Mate, Are Anti-Union
Now, full disclosure, I am in a Union, and it's the best thing to ever happen to me. So I may be a bit biased, but Unions are the reason why there is such a large middle class today. By working for the rights of the employees, they have ensured ethical business practices, leading to better quality of life for the workers, and not just union members. They set the bar higher in the industries they affect, with better trained workers and more reliable employing.
Not only do they provide workers with jobs and better pay, they provide them the opportunity to make a positive influence in the local economy: by building up rainy day funds, when times get tough, unions become the backbones of the companies that work with them, providing them compensation when they have to underbid to get a contract, amongst other things. They also maintain relationships with medical companies to ensure not just their members are covered, but that their families are as well. In essence, they do all the things that the government had tried to enforce over the past 8 years, but responsibly and privately.
He Would Increase The Debt by Five Trillion Dollars
This is a huge one: according to another Bloomberg report, Trump's budget would end up adding $5 trillion to the national debt by the end of his first term. Even Hillary's plan would only increase it by $200 billion. Not saying that's necessarily good, but when a Republican would have more deficit spending than a Democrat, something is wrong.