WI if the Ottomans emphasized expansion more directly north and east, rather than west and south. How would the wealth, power and longevity of such an alternate ottoman empire compare to OTL's version.
Here's what I had in mind - In the south, the Ottomans never go further than northern Syria and Iraqi Kurdistan. To the west, they take Bulgaria, Greece and Romania east of the Carpathians but never conquer Transylvania, Hungary, Belgrade, Bosnia, Kosovo or Albania. Their western frontier runs along the Carpathians, the Danube, Morava and Vardar and ends somewhere in Greek Epirus or southernmost Albania.
It seems to me that this still nets the richest part of the Balkans agricultural and pasture land for the Ottomans, while also providing a large protective glacis on the littorals near Asia Minor and Constantinople. At the same time, it avoids the Skanderberg wars, most wars with Hungary, and just about all wars with the Habsburgs. I do not think they western Balkan and Hungarian areas they leave out of their empire will coalesce into an overpowering threat or even one as expensive as they faced in their OTL European frontiers.
However, the Ottomans push as far north as they can from the Black Sea coast, seeking to control all the Ukraine, and going as far up the Dnepr, Don and Volga rivers as they can to, even to Muscovy if that's possible. This should get them even more good pasture and farmland, and preempt a later coalesence of later Russian strength, by occupying as much intermediate buffer territory as possible while the Ottomans are in their relatively dynamic, expansive phase and the Muscovites are less developed.
To the east, the Ottomans subjugate the Caucasus, advancing at least as far along the northern and southern shores of the Caspian to meet up with ethnically Turkic areas. Possibly the Georgians become a big source of Janissaries in place of the Albanians. To the southeast, they subjugate the Safavid Persians and crush all resistance in western and central Persia at least. In the south, they don't mess with Egypt, Palestine or the Persian Gulf. In Asia, I think this leaves them with relatively weak, nonthreatening neighbors to the east and south, while crushing their main rival, the Persians, which hopefully results in savings later from not needing to fight and protect against a centralized Safavid state.
This concept is inspired in part by separate comments years ago by Abdul Hadi Pasha where I believe he said the invasion and occupation was a strategic overextension for the Ottomans, and where he said that the Ottomans could have conquered Persia, and probably won a "peace dividend" from not needing to cope with a Safavid threat.
I also had the idea that Mameluke Egypt was pretty weak and nonthreatening to the Ottoman heartland, that the eastern Balkans were richer territories than the western, and that in the long-run, Russia was going to be a greater, more deadly threat than enemies like Austria or Hungary in Central Europe.
So my guess is that if the Sultans from the 1400s through the 1700s focused on this, more eastern, vision of empire, the Ottoman Empire would have been wealthier, more militarily secure and might have lasted to this day, even if not at its peak territorial extent. What do you think?.