Trump is not the best candidate for the job.
However, Hillary is completely crooked and for purchase through her Clinton Foundation. She is the epitome of influence for power and now she wants the most powerful job in the world so she can sell that influence too...
Bernie is no different except compared to Hillary he is a petty criminal. He has compensated his family and friends using his connections.
Rubio and Cruz are lifetime politicians. Sure, nobody likes Cruz but neither of them got done in the legislature what they are promising to get done in the White House. That is like having someone completely fail at a job yet expect to get promoted to the next level of responsibility.
Trump's ego is a problem. It is always about trump, not about America. But he knows how to negotiate, he understands international trade and business, he has a proven track record of putting people on jobs and getting them done on budget and on time. He cannot be bought, he already has all the influence he needs. He buys politicians. So from the pile of crap I get to choose from, sadly it looks like trump rises to the top of the litter.