If the Ottoman Empire still existed, would ISIS exist?This is an awesome question. Seriously. There's two ways to go about this..
Ottoman Empire does industrialize- The Ottoman empire really collapsed due to their failure to industrialize. They had a lot of manpower at the eve of WW1, but not the resources necessary to adequately use this power. If they had industrialized, they probably would've survived and if we are assuming that they are strong and developed, ISIS probably wouldn't have even emerged, nor would Al Queda.
Ottoman Empire doesn't industrialize- The Ottoman Empire fell in 1920. Needless to say, it doesn't matter how many men they have. ISIS would meet the Ottoman army with AK47's blazing....and would've massacred them. They would've absolutely risen, and beaten any opposition in the Middle East, including the Ottoman Empire.
No, the Ottoman sultans also claimed the position of Caliph and as there is only one true caliph in Islam at any given moment, "Caliph" Abu Bakr al-Baghdadi would be seen by Sultan Bayezid III as some troublesome usurper who should be quickly removed. Also, the very specific school of thought that ISIS/IS/ISIL/DAESH/(Call them anything) and most other Islamic terrorist groups subscribe to, Wahhabism, is a phenomenon that comes solely from Saudi teachings which are followed by very few outside that country. There would be even fewer adherents if the Ottomans stayed in power and continued to fight the Saud family as they did historically. Wahhabism is basically an extremely fundamentalist interpretation that is comparable to something like Christian Science: totally out of the mainstream. An oppressive regime like the Ottomans became in their closing days would have clamped down on such beliefs.
However, that's not to say that the Middle East would be a happy and nice place today. The Ottoman leadership became increasingly discriminatory and paranoid in the last few decades of their rule, reversing centuries of tolerant policies. Evidence? Armenians.
Probably not: Ottoman–Wahhabi War (the methods of how the First Saudi State came to power very closely resembles the methods of ISIS)
But then who knows given the shadowy nature of ISIS
If the Ottoman Empire still existed its doubtful the Arab countries or maybe even Israel would exist as the victors in World War 1 drove the Ottomans out who were then siding with Germany and divided up the Middle East between themselves, mainly the British and French I think.
The current borders say of Iraq and Syria were drawn by the British and French I think and the borders remained intact when these nations became independent nations.
ISIS would not exist no, the Ottomans were ruthless with any uprising in their Empire.