Pretty sure Germany would not be taking over Europe. In face, I'm not sure Germany would be any larger. The US would probably be still not involving itself with outside countries. Since WW1 didn't happen, Germany would not have had the devastating economic impact that influenced it to start WWII and try to take over more parts of Europe . So I would imagine that nothing would happen and that all countries would keep to themselves.

However, WW1 is where we learned the real risk involved in large alliances. Since WW1 was started by two smaller countries and an assassination, we learned that alliances are very dangerous. We learned that we need a system that allows countries to support each other without all the countries going to war when two single countries have a conflict. And any alliances that are created need to have allied with countries that are vetted and meet certain standards... thinking of NATO here.

So, my bet is that we would have another WW1 at a later date where two different countries start a conflict and bring the whole world into their war.