I will try to explain my point of view from a historical point. - Don't get me wrong, I do not even like, what he had done and I hate what he had done for the world in his dictatorship, no question!
But from the history, you only can say, that his politics were exactly what the Weimarian Republic needed. He was a Keynesanian economist, he did exactly, what other countries would had done in this time in this crisis of the state.
Also his national politics weren't as bad as we think. Russia, France, Italy, Spain, they did nothing other than a very strict nationalism. And yeah, it is right, war establishes work space for those, who have no work, as well as the building of the highways.
So politically - he did all the right things for bringing the Weimarian Republic back on the map of global players. His fail was only his extreme version of his politics and his goals.
As I said: I don't like him, no, I have to say, I really hate him, but the politics in this time were those, which other countries, also in Amercia, did as well.