I think you overestimate the importance of a Euro hegemon, as well as the level of hegemony that Germany is taking here. The Kaiserreich will be just as tattered after the war as Britain is, and the Royal Navy will still be more powerful than the Kaiserliche Marine. While the pound is in danger of collapse like in Place in the Sun 1.0, that's less an opportunity for Germany than one for the US, which despite its comparatively small military was quite the economic superpower even then. In addition, Wilhelm will have to deal with the inevitable French, Russian, and Danubian conflagrations post-war. There will be little attention on the Western Hemisphere, especially since the Monroe Doctrine is even more secure now that Europe's nations have effectively shot themselves in both feet. If anything, US intervention will be in the form of financial investment in Europe, as Britain is no longer in any position to pretend to be a counterweight in Central and South America. Now, I could be wrong (Germany sending arms to their Mexican warlord of choice would feel very in-character), but I don't think we'll be seeing any US interventions beyond the OTL gunship diplomacy around Veracruz and possibly Tamaulipas, as well as a possible expeditionary force to murk Pancho Villa.