I don't think Germany could have won the Great European War had its 'Blitzing' offensive into France failed (World War 1 / First Weltkrieg is always so pretentious sounding to me... especially taking into account the REAL
World War

).
France got caught off guard and hampered by bad logistics and strategy on the national level. The French generals and politicians failed France in that war (as usual

), not the French soldiers whose professionalism and courage has stood since Napoleon.
Without France, Britain has no purchase onto the mainland of Europe save Russia and we all know the debacle the BEF got into on the Russian Front or at Gallipoli during the Anglo-Ottoman War. But if France can hold on for the British to get their stuff together Germany is now facing Britain, France AND Russia, the three largest empires on earth at the time with only an Austria Hungary that is wracked with ethnic division and of a generally poorer quality army.
With France in the fight Britain has a much greater case to make for blockading Germany to the Big neutral powers like Japan and the US or whipping up anti-German sentiment which the notoriously racist and Anglophile Woodrow Wilson would have been glad to use rather than what happened, namely the German American community successfully swaying public opinion for 'fair, equal and open trade'. Certainly glad the prick got booted in 1916 by Hughes.
Although it would be interesting to see what the world would have been like without the quick victory over France and the Czar packing it in in 1916 when things became incredibly obvious that victory was not in the cards. There certainly wouldn't be a Mittleafrika succeeding from the ashes of the 'Congo Free State' and the existing German colonies.
(ooc: I'm going to try and fix the whole 'France annexed by Germany' bit)
I think the Kaiserreich would also have lasted a LOT longer win or lose due to Wilhelm not going off the deep end and trying to 'annex' France. In the history of Incredibly Obvious Bad Ideas trying to annex 40 million people who mostly hate your guts in the West while you're also trying to annex 40 million people who mostly hate your guts in the East (Breast-Litovsk)... well... the only thing that tops that was the Pacific War insanity with Japan vs the World. Germany would have walked off a cliff had the Reichstag Revolt not happened.