Archduke Ferdinand Lives: A World Without World War One by Richard Lebow has a situation like this as one of its scenarios.
The gist of Lebow's thesis is that the July Crisis was the last major crisis that could've caused a war between the Great Powers (Morocco Crisis, Annexation of Bosnia-Herzegovina, First and Second Balkan Wars).
If the Archduke wasn't assassinated, the Great Powers would gradually shift their attention away from the Balkans toward domestic reforms at home, and instability in Russia to some extent. The UK was struggling to resolve the Irish question, the Ausgleich was set to be renegotiated between Austria and Hungary in 1916, and Germany was divided between a SPD that controlled parliament (and thus the power of the purse over the military budget) and the Kaiser who cared about "Germany's place in the sun" more than the SPD's welfare programs.
The naval race between the UK and Germany was winding down by that point, and a few more years of industrialization in Russia would have closed any mobilization advantage Germany had on the Eastern front.
I haven't touched on France, Italy, or the Ottomans because none of them has the geopolitical strength to start a great-power war on their own. A one on one conflict between France and Germany over Alsace-Lorraine or Italy and Austria over Tyrol+Dalmatia would give too much of an advantage to Berlin and Vienna for Paris or Rome to try anything on their own.
The Ottomans were set to receive a set of modern naval vessels in late 1914 (blocked by Churchill OTL due to naval demands of coming conflict) and the London had reached an accommodation with Berlin over the Berlin-Baghdad railway.
In a best case scenario, Kaiser Wilhelm's II's bellicosity leads to a sudden end of the Kaiser's power over the military, or gradual reforms make the Chancellor more responsible to Parliament than the Kaiser.
If Franz Joseph I passes away around the same time as OTL, Franz Ferdinand might get a chance to break the power of the Hungarians by implementing universal suffrage in the Kingdom of Hungary, and/or abolishing the Kingdom during a renegotiation of the Ausgleich to make A-H a more equal federation. Galicia, Transylvania, Bohemia, and Croatia could be raised to the level of Bosnia-Herzegovina in a "United Kingdoms of Danubia" with devolved regional parliaments in a decentralized or federal empire and a common Habsburg head of state.
Russia's system is probably the least stable ancien regime of 1914 Europe, so sooner or later Czar Nicholas II would be forced to make reforms or step down. Russia could evolve into a Constitutional Monarchy with a more reformist Czar, or abolish the monarchy and just become a republic. Without WW1 the Socialist-Revolutionaries would still be the largest revolutionary group, their land reform plans made them popular with Russia's peasants.
The SRs believed in parliamentary democracy and a gradualist road to socialism, so their "revolution" would've looked more like the German SPD than the Bolsheviks of OTL. The OTL Provisional Government looked to the United States as a possible model to restructure the Empire, so Russia might be turned into a federation with varying levels of autonomy for Poland, Finland, Central Asia, etc.
If all these reforms go well, Germany could end up as a prosperous Constitutional Monarchy at the center of a reasonably democratic Europe. Colonialism would last much longer, the decline of the landed aristocracy would be much slower. Russia's problems with antisemitism would likely continue throughout the first half of the twentieth century, but moves to grant Jews civic equality could be an analogue of the civil rights movement for TTL Russia.