Dimwitted racist disgrace is actually a pretty good summary of Trump's character profile. My personal description of him would be far less elegant, and vastly more offensive.
Not to get into a political discussion but I think Trump is doing his job perfectly. I think he's a blocker that is basically a magnet for all the negative attention aimed at Republicans. Just about anyone else the Republicans nominate (except Palin or Bachman) is going to look like an entirely reasonable person by comparison. Keep your eye on the ball. Trump doesn't have it.