Trump affirmed tonight that he really, really likes Putin. Putin has invaded countries and killed reporters and political opponents ("Well do you want me to tell you what Obama's done," Trump asks in rebuttal) and yet, as Trump says in support of the man, Putin has an 82% approval rating. This gets to the essence of what is most troubling about Trump.
Trump doesn't necessarily aspire to a traditional kind of dictatorship. He seems more interested in a dictatorship of the majority. This is the difference between a democracy and a liberal democracy.
In a liberal democracy, the majority gets to rule but even minorities have rights like freedom of speech, independent press, a judiciary that answers to its own conscience rather than a president or prime minister's. The majority doesn't rule. The majority merely chooses the people who will define policy (to the extent that this policy doesn't take away the rights of minorities).
Trump has threatened to sue reporters that criticize him, banned selective news organizations from his events, presided over rallies in which crowds have called for the execution of his political opponent Hillary Clinton, and has himself called for a ban that would end freedom of religion.
Donald Trump does not just show a lack of support for rights and freedoms of everyone - including minorities. He shows a lack of interest.
Given this, it's no wonder that he admires Putin who shows no respect for rights and hates Obama who not only shows an interest in the rights of minorities but is one. The only reason that Trump is just a bully is because he hasn't yet won office.