First, I would have to take issue with the term "achievements." The definition of an achievement is "something accomplished" and carries with it a positive connotation. I have a hard time seeing Hitler's programs as accomplishments because they were not enduring and he was not the first German to advance them. That's a quibble, though...not really here nor there.
As for the ideas advanced, let's take a look:
1) Economic Recovery -- Germany's economy was ruined by the first world war (huge payments required by the allies) and further pummeled by the great depression. Unemployment held at 30% and inflation made German money worthless. Hitler was able, by controlling the economy, to reverse these trends. His massive public works projects and emphasis on military buildup put people back to work. When people are working and earning money they tend to be less radical; therefore, Hitler was able to cut down on dissension and political opposition by reversing Germany's economic down-slide.
Of course, during the war he simply took what he wanted form the countries he invaded (well, forced the people there to sell it dirt cheap back to Germany.) Forced labor was remarkably cost effective as well : )
It is hard for me to see this as an accomplishment...as a result of his policies German manufacturing was leveled during the war and industry hamstrung. His policies had the long-term effect of ending the German economy.
2) National Unity -- Germany, throughout history, has been a fractured entity. It is only recently that it has been able to function as a unified body. Hitler, through destroying rivals, abolishing unions, outlawing political parties, and running an incredible propaganda campaign was able to unite the German people. It can't be forgotten, either, that he was able to consolidate German nationalism by vilifying foreign governments and scapegoating the German Jews.
I don't see this as an accomplishment, either. Because of his plan Germany would be split apart after the war and not be united for 40 years or so.
3) National expansion -- Germany lost territory during the first world war, including some very economically productive areas bordering France. Hitler was able to get that back, as well as the "peaceful" annexation of Austria. Had he stopped there he probably would have gotten away with it. At its height, he had, indeed, expanded the German nation well beyond its borders.
Again, this is not a real accomplishment, though, as it was all taken back after the war (and then some.)
4) Collective Organization -- To be frank, I am not sure what you mean here. The only type of "collective organization" I can think of are trade unions. Under Hitler, these were made illegal. Though this might be considered an "accomplishment" by some fat-cat business types, it's hard for me to see it that way.
I hope these ideas bring something to the discussion!