Well...
No U.S. involvement in WWI
-->Stalemate in WWI
--> negotiated peace in 1918 with no oppressive terms on Germany
--> no WWII.
---> strong Germany in 1940's and 50's
---> no Soviet domination of Eastern Europe in 1940's -80's.
The crystal ball, however, begins to get a little fuzzy by the 1980's
Would a strong Germany and stronger USSR have faced off in the late 40's? It gets fuzzy.
Yes,and that isn't even taking into account the communist agents in place in Germany and other European countries that were determined to overthrown their goverments. All of which makes the whole theory so much HorseHillary.
The Austrian Kaiser, Karl, would probably have raised the Slavic peoples of the Empire to equal status with the Germans and Hungarians, thus effecting a "Triple Monarchy" which had been Archduke Franz Ferdinand's intention (had he not been murdered by the Serbs).
Also, one more thing to consider about the outcome of WW I: the various Arab states whose citizens are now wreaking havoc throughout the world would not exist. They would still be part of the Turkish Empire, which had been secularised by Kemal Abdul Ataturk. The Holy Land would have continued under Turkish administration, with free access granted to members of all religions.
People do not like to contemplate this scenario, because it increases the enormity of Woodrow Wilson's crime against Europe and Christendom. It also suggests that America was on the wrong side in at least one war -- and that the most important one in history.