I'd like to propose a scenario that would be interesting to analyze for its short-term consequences but also for its long term consequences into the 20th and 21st century.
The scenario for early Ottoman collapse comes form this PoD I contrived:
Instead of France leading an anti-British coalition to achieve revanche while the American rebellion was going on, France instead seeks to expand elsewhere while Britain is busy.
France had ties to the Ottoman Empire in the 18th century but still was making trade agreements with Russia and beginning to see Russia as a more useful power.
So, the French old regime, interested in collecting garden spots like Egypt, Syria, Tunis, goes to war on the Ottomans, and encourages its allies from the last war, Spain, Austria and Russia to do the same, to help with the carving. Austria's zone of operations is the Balkans, Russia's zone is the Balkans and Caucasus, and Spain's zone is Morocco and Algeria.
The Ottoman empire is significantly rolled back over the 25 years from 1775 to 1800, either collapsing entirely or being reduced to a Turkish Anatolian rump.
The British are rather busy with the American rebellion for the first 10 years of this and not in a position to support the Ottomans against this grand coalition. And then, once the British have defeated/settled the American rebellion the prospect of a war against the large coalition is too daunting, and the Ottomans have lost so much prestige, that at most Britain prefers to carve its piece of the pie (likely Mesopotamia and coastal Arabia) rather than try to prop up the flagging Ottoman cause.
The coalition is also so formidable that the Prussians opt to say neutral and out of the way.
The Balkans, Caucasus, Levant, Egypt and North Africa are made into colonial possessions of European powers or made into client states of same.
Within this general outline, how do you see things playing out, how do you see European power politics developing and Middle East-North African politics and society changing?
What would cause the anti-Ottoman coalition the most difficult challenges and give the Ottomans their closest shot at a comeback?
Would we have the French Revolution on schedule, or in any case by 1800?
How would the British empire and British diplomacy and economy develop.
Now humor me, assume the Ottomans have basically lost, and fast forward into the 20th century.
I would assume, even with the details of the American and French Revolutions being different, that modern European nationalism would come into existence over the 19th century. Every national group in Europe ends up with at least some national aspirations by the 20th century.
In the meantime, the Middle East and North Africa have gone through generations of existence as separate units oriented towards their European dominators rather than towards Istanbul or each other.
It's the Europeans, not Turks, who kill off the Janisarries. All the internal attempts at reform that the Ottomans tried out are missed.
There is no Hamidian era of reform, recentralization and glorification of pan-Islam.
Will the states identities of various regions of the Middle East be more dominated by local nationalisms than by pan-Islam or pan-Arabism compared with OTL?
Why or why not?