Okay, the POD here is that Joseph II marries someone else. I don't know if it makes sense, or if it's historically accurate, so please don't flame.
Extracted from Ludwig-Karl Hapsburg: An Austrian Hero
Ludwig-Karl Hapsburg lived from 1780 to 1850, and reigned for 52 of those years. He witnessed the disbanding of the Holy Roman Empire, the Napoleonic Wars, and ensured that his beloved Austria would remain a world power, through military, civil and economic victories at many places, from the halls of power at Vienna to Austerlitz and Constantinople, from the Hofburg and Schönbrunn to the bloody fields of Thrace.
What should we remember him for? His epic military victories, at Austerlitz against Napoleon and Constantinople against the Ottomans? His transformation of Austria into an industrial Great Power? His son Augustus, who maintained Hapsburg dominance over northern Italy? Purveyors of the 'Great Men' theory of history use his name as certain proof of their theory, for the things that he did have had immense effects on the world.
None of those things.
We should remember him for what he was.
A hero to his nation, a father to his men, a great man, unsullied by mud-slinging, who we can all look up to as glorious.