Wilson cannot be held responsible for WWII. It was a European problem. It would have happened with Hughes as president as well as with Wilson. It would have happened if we would have entered the war in 1914 or stayed out all together. It would have happened with the complete adoption or complete rejection of the 14 points. Even a Marshall plan type response wouldn't have prevented it. Too much nationalism and distrust in Europe at the time.
On this point I disagree. Imperial Germany probably would have "won" World War I had the US not sent in troops. By "won" I mean that the monarchies would have remained and there would have been
no dismemberment of continental Germany. It is likely that there would have been a negotiated settlement. We might have seen a more hostile France, however.
Colonies are another matter; Germany's colonies were not particularly profitable and were very sparsely populated. The Soviet Union would have been weakened.
The only really strong nations would have been Japen and the US, with the Second Reich being strong on paper, but greatly weakened. British decolonialization may have started two decades earlier.