Trump was typically more moderate on the economy and tax policy, abortion, military. His stance on immigration is the more conservative than the rest. Rubio and most of the rest were very strict on abortion, had typical Republican ideas on tax, support interventionist military campaigns, but had varying but less conservative stances on immigration. Although Trump's behavior was boorish and comedic at times, that appeals to Americans and gets you media exposure. Just like the coolness of Obama and Bill Clinton.
If the DNC didn't engage in shenanigans, wouldn't the Democratic demagogue have had a much better chance at winning than Hillary?
Which is interesting, because Kasich is not in any objective sense a moderate. (I live in his state) Relative to the rest of that field, sure, but that's what is alarming.
Also, I don't think anyone on the left needed a new, worse bad guy. We've had plenty sitting in Congress.