Sans a U.S. entry, Europe would have fought itself into oblivion. U.S. entry into the war is probably a huge net positive in that regard.
Not true. A non-US intervention scenario is ceteris paribus a German win within a year and a British withdrawal from France. The British Empire is intact, Germany takes over the French and Belgian colonies.
I assume Germany would take control of all of Belgium. What of France? Is Germany constantly then dealing with uprisings in the various parts of its continental empire?
The Germans didn't incorporate France in 1871 (save Alsace-Lorraine); do you think they would have acted differently without Bismarck?
They would have acted somewhat differently I'm sure, but not to try to incorporate all of France. But with Germany already holding Alsace-Lorraine at the start, what would have been the terms they demand from a French surrender?