I don't think Trump would be a particularly good president, but I reckon it will be better for the USA in the long term. The DNC admitted to rigging the democratic nomination in favour of Hillary, thereby rendering the whole process redundant and screwing a genuinely decent candidate in Bernie Sanders, not to mention giving the finger to his support.
I see plenty of people in my Facebook feed who think the US is in dire need of fundamental change, yet they're willing to let the cycle of Bushes and Clintons continue because they've been frightened by the media. Hillary is the most compromised candidate I can think of, already anointed by a party that doesn't want the idea of real change to take root, and a vote for her is a vote for "as is".
A vote for Trump may be the last chance the electorate have of making a real protest, a message to the establishment that will actually make an impact. Because 8 years down the line, the Republican party will fix their nomination system so that another populist candidate can't happen. The Democrats won't have to, because they admitted to rigging their primaries and nobody seemed to care.