Two more factors: The Ottoman Turks considered themselves to be the successors of the Roman Empire. Before they captured Constantinople, their territory was known as the Sultanate of RumSultanate of Rum. After capturing Constantinople, Mehmed II called himself the Caesar of Rome (Kayser-i RumKayser-i Rum). Constantinople had been the capital of the Roman Empire for more than a thousand years. So moving the capital would amount to abandoning that claim.
Although the Balkans had not been ruled for long by Moslems, they were better watered and hence more agriculturally productive and valuable than most of the Arab world. So it made sense to have a capital near that area.