Relatively speaking. As far as I know, the Netherlands did (slightly) more to help Germany (and by extention, the Central Powers) than to help the Entente. They didn't help all that much, but still.
However, this is just some tidbit I once read, so I could easily be wrong.
There are three german dialect groups: Upper German (divided into High Franconian, Alemannic German and Austro-Bavarian dialects), Central German (divided into West Central German (including Luxembourgish) and East Central German dialects), Low German (divided into West Low German (these are all North Low Franconian, South Low Franconian and Low Saxon dialects) and East Low German dialects). The modern High German is based on Upper and Central German.
One POD could be a failed murder on Prince William of Orange ( ''the silent'') in 1884. Perhaps he would lead the success full defend of Antwerp. Parma and his successors losing more rapidly grounds. Amsterdam and Holland never gain so much influence in the North Netherlands. William of Orange and his successors could gain more influence in the new state and could fulfill their dynastic ambitions by conquering/marriage and diplomacy to carve a large German Principality /Kingdom out of the patch work of German States or connect the Netherlands in to a larger (North-) German dominion.
Any other time is less likely. The North Netherlands develop from the 17th century on wards a strong national conscience. German Principalities were economic financial far behind the Dutch republic and were mainly providers of soldiers and low paid laborers for the Dutch in the 17th to the 19th century.
Would twisting the problem upside down work - Germany (or parts) PART of Netherlands?
Have Frederick William I from Prussia conquer Netherlands after he creates a professional army. He ruled Prussia either in the later stages of the thirty years war or directly after that. He would probably be the best choice because he spent a good amount of his youth in Amsterdam. That would set up a very interesting occupation scenario.
He was never a 'real' king to begin with, and only chosen as anti-king because he was basically powerless. There's no chance that he could start a dynasty, and a few more years of him pretending to be German king has no influence on the national identity of the Dutch. Sorry.Maybe a somewhat earlier pod would work?
Let William II of holland (http://en.wikipedia.org/wiki/Count_William_II_of_Holland) survive much longer than 1256, till lets say 1308, and so letting him stay king of the HRE for a much longer time and also let him become effectively the king. Maybe this will start a feeling that the Netherlands is a central part of the HRE.