May I ask what aspect of the calpihates are you refering to? Geographic, cultural, military or other?

Coming from a country which was occupied for only (?) 145 yrs by the ottoman turks (compared to say 500 yrs of Serbia) we probably have a different kind of perception about an ottoman caliphate (along with many other ethnicities who lived under their rule) than other, luckier nations, who have not experienced it.