Hitler had two areas of greatness, to whit, public speaking and leadership.
- His talents as a speechwriter and orator were immense, and he used them to their full advantage. Without that sheer force of persuasive power, the sheer belief in the rightness of his cause, the Third Reich could never have been built.
- He always picked the right people for the right jobs. Early on, Hitler was well aware of his lack of organisational skills and therefore delegated magnificently. Use of Joseph Goebbels for propaganda, Wilhelm Canaris for the Navy, the aforementioned Prussian High Command, Heinrich Himmler for security, Joachim von Ribbentrop for foreign affairs - a much underestimated masterstroke! - and other subordinate positions were all impossible to better given the available resources of the time.
However, oratory cannot win a war and with growth in power Hitler's megalomania become more and more intense. As that power was put under pressure first by the British with the repulsion of the invasion forces in 1940/1941 and later by the full weight of the Allied combined military might and expertise, he cracked. He began exhibiting more and more overt signs of mental dysfunction - the aforementioned anti-semitism for one, since his obsession with what been merely a political tool became an article of faith, the micromanagement that has already been discussed and his new obsession with Russia.
It is invariably a mistake to believe one's own propaganda. This was Hitler's downfall, and a very ordinary one it was, too. He was not a great man. Managers seldom are.