I think it would complicate Nazi control. Prince Wilhelm of Prussia (Wilhelm Friedrich Franz Joseph Christian Olaf; 4 July 1906 – 26 May 1940) was the eldest child of Crown Prince Wilhelm of Germany and Duchess Cecilie of Mecklenburg-Schwerin. At his birth, he was second in line to the German throne and was expected to succeed to the throne after the deaths of his grandfather and father, both of whom, however, outlived him.
In May 1940, Wilhelm took part in the invasion of France. He was wounded during the fighting in Valenciennes and died in a field hospital in Nivelles on 26 May 1940. His funeral service was held at the Church of Peace, and he was buried in the Hohenzollern family mausoleum in the Antique Temple in Sanssouci Park. The service drew over 50,000 mourners, by far the largest unofficial public turnout during Nazi rule in Germany.
His death and the ensuing sympathy of the German public revealed that despite years of Nazi ideologic indoctrination large parts of the German society still were affectionately bound to the former German royal houses. Shortly after Wilhelm's death, a decree known as the Prinzenerlaß, or Prince's Decree, was issued, barring all members of the former German royal houses from service in the Wehrmacht.