In 1000 years Adolf Hitler will be remembered as...

[bore]

We should remember that the movements of history aren't all one way. There are plenty of examples of people who have become more controversial in public memory recent years, for instance Christopher Columbus. Also Hitler was, all in all, rubbish, he was a pretty poor general who got lucky for a year or so and Mein Kampf is as well as being one of the worst books ever written, also one of the worse written. Leaving aside morality, in terms of sheer competence there is no comparison to people like Julius Caesar, Genghis Khan and Napoleon. If you're looking for the 20th Century Caesar or Alexander the Great I think you'd be better off with someone like Lenin.

The important thing when it comes to moral judgements on history, though, is that it isn't based on how long ago it was, but how recognisable the moral universe is to the historians. We can see this by the degree of judgement passed in the west on the Romans, and especially the Romans and their relationship with Christianity and Judaism, compared to the activities of, say, Chinese  and north american empires at the same time. This is because our current morality is largely based on Christianity and Greek philosophy. Similarly you are far more likely to see judgement of Medieval monarchs than of Genghis Khan, because the former were Christians and thus at least in outline understandable to us, the latter was not. We basically inhabit the same moral universe that the people of the 1940s did, so Hitler is an even starker case. As long as this remains the case, there will be people lining up to condemn him.