Peter: I will play your game of What If. I think that the hauben would have remained for officers on parade. We see many post war pics of officers wearing their pickelhauben on state occaisions. Regarding a German victory on the political scene. I would venture to say, large reparations for the French with reduced military forces. This is what happened in 1870, at least with reparations. In the east, obviously they had already annexed huge territories as a result of the Treaty of Breast Litovsk. No Hitler, no reason for Hitler as there would not have been a Treaty of Versailles.
What to do with the Brits??? I see them going it alone just as in WW2. I do not see the technology existing for a naval invasion. Besides, the War at Sea was won by the Brits. The German surface ships did little after Jutland. Perhaps an attempt to starve them out with U-Boats? Bomber raids as in WW2? Remember the Brits also have Canada, Australia etc etc. Perhaps a breathing period for both sides before going at it again. Perhaps nothing if the Germans are occupied with their new eastern territory. Traditionally, the British can not accept one country dominating the continent though.
Of interest, would be what to do with the Kaiser. Ludendorf and Hindenburg were running the country by mid war. The Kaiser was a figure head and had never proven to be the great war lord, the role he loved to play. What if..... an interesting game to play. Brian