My viewpoint:
The Von Schlieffen plan works, the Germans encircle the French army, the British are rolled back to the coast and evacuated. The French government collapses again, and the monarchists and the communists fight in a power struggle for control over the French government. Germany consolidates power over the Lorraine and Rhineland areas in a territorial cession in the peace accords. The French army is paroled from their encirclment. France falls into a civil war between the various factions. Russia, seeing that it's stalwart ally has falled, continues on with the war and pours vast resources into stabilizing the front. Germany transfers all but a few scattered units to the Russian front, conducts a break-through along the Southern front and conducts another encirclement of the Russian army. The Russian monarchy collapses, the Russian Civil War begins early. With Russian effectively out of the war, Germany consolidates it's borders by occupying Poland, Latvia, Lithuania, and Estonia, which are granted the same status as other provinces within Germany by the mid-1920's. Italy, now on the wrong side of the fighting, finds itself involved in a war where the Germans and the Austro-Hungarian forces are able to crush Italian resistance, Italy sues for peace. Austria secures it's hold on the Balkans and the Ottoman Empire succeeds in securing portions of the middle east and parts of the Baltic.
Britain fights on, tries to get the U.S. involved, U.S. refuses to get involved in a civil war in Europe, signs treaty with Germany, Austria-Hungary and the Ottoman Empire to remain neutral in Europe for consessions of the French colonies. U.S. expands influence in the far east, annexes the French colonies in the far east, leaves Africa to the Belgians and the Germans. U.S. provides "protection" for the colonial interests of U.S. companies from the turmoil of the French civil war and continues to engage in a "cold war" with Japan for naval supremacy in the far east.
Tanks are not invented, the aircraft continues to evolve at a snails pace. Super-battleships are developed as the Naval treaties are abandoned. Aircraft carriers are slowly developed, first by the British, but adopted by other powers by the mid to late 1920's and early 1930's. Germany builds the Graf Zepplin aircraft carrier and builds high-altitude Zepplin bombers for naval engagements with naval "Zepplin Tender" ships with masts and aerials for servicing Zepplins at sea.
The Communists consolidate power in France and Russia by 1928. The stock market does not fall in 1929, but manages to continue on until the mid-1930's until the mass fraud is found, the world banking system flounders on massive bank failures, the Great Depression begins after the U.S. dust bowl days, and WWII starts in the mid 1940's as a Polish uprising against the German occupancy and supported by the Russian communists.
Japan has secured Manchuria, and waits until the fuse in Europe has been lit to launch an invasion of China. Japan invades China as a liberation army to kick out the colonial powers (especially the U.S., Britain, and Germany). Russia and France sign another treaty and include Japan in a non-aggression pact and mutual alliance against Germany, Britain and the U.S.
Italy signs with the Ottoman Empire against the British and joins forces with France and Russia for territorial gains in North Africa and the Balkans and to kick the British out of the Mediteranean basin once and for all.
In Spain, the civil war begins with the economic collapse in the 1930's and continues with neither side gaining any ground despite military aid from Russia, France and Germany toward various factions. Ultimately, the Spanish civil war is resolved with the Monarchists gaining control as French and Russian aid for the Communists dissolves and military aid for a constitutional monarchy from the British, Germans and U.S. secures peace. Spain remains neutral during the ensuing conflict.
The allied forces of the British Empire, Germany, and the U.S. wage all out war against the Russians, French, Japanese, Ottomans and Italians. The British Empire launches an invasion of Russian territory as liberators from the communist powers through India, led by Indian and Commonwealth troops from Canada and Britain. The Austrialian and New Zealand troops with U.S. allies engage in an island hopping campaign against the Japanese in Malaysia and Indo-China and ultimately they gain allies with the Chinese forces of Chian Kai-Shek, forcing Japan to sue for peace in 1951 with the concession of Hokkaido, and Okinawa to the Americans and British, respectively. Russia collapses as the Communists lose the Balkan oil fields to a combined assault from the British and German forces who penetrate deep into Russia. Italy and the Ottoman empire sue for peace in 1949. Italy adopts a parlementarian form of government. The Ottoman empire adopts a constitutional monarchy and surrenders most of the territories outside of Asia Minor and a strip of territory in the Balkans. The Balkans are reincorporated into the Austrian-Hungarian empire, which also adopts a constitutional monarchy and Germany remains under the rule of the Kaiser. Russian Communist forces finally surrender after Lenin, Trotsky and Stalin are all killed in a surprise daylight bombing raid by the U.S. from across the North Pole.
France, after a failed amphibious invasion attempt on England and losing ground against the Germans in the Ardennes, sues for peace in 1952. France's communist party collapses with the peace treaty and France remains in a fractured parlementarian system with a collaboration government in power with various wary allies vying for supremacy.
The U.S. finds it's industrial might and maintains a vast colonial empire over bases across the Pacific in Indo-China and finds itself involved in the Vietnam war in the mid 1950s. The U.S. continues to expand it's influence in South America by allowing various states to petition for state-hood, with Bolivia, Columbia, Guatemala, and Brazil petitioning for State-hood in the 1950's and being admitted in 1957.
China, after Chian Kai-Shek allies with the U.S., Britain and Germany, consolidates power, purges the Communists, and establishes a right-wing dictatorship. China falls into civil war again with his death in the 1950's, the communists again rise to power, but are defeated by the constitutional monarchist powers and the re-establishment of Imperial China as a constitutional monarchy. The Forbidden City is established as the Parliament with the inner city the Imperial Palace.
Peace is roughly established throughout the world by the mid 1970's until the oil revolts in the Middle East, followed by the cessation of colonialism by the major powers and the ceding of various out-lying colonies to self government in the early 1980s. Minor civil wars and territorial wars continue into the mid 1990's.
Mexico petitions for state-hood following a military coup and civil war in the 1980's and after military intervention by the U.S. after the civil war spilled over into Califoria and Texas. General George Bush is in command of the U.S. expeditionary forces in Northern Mexico, while Commander Condolezza Rice is involved in pacifying the Oaxaca and southern areas of Mexico.
The first non-North American President is elected in 2008.
Aren't alternative histories fun to speculate about?
– yeah, me too. I rethought Spain already as it didn't do justice to Franco.