What elements aided, limited, the spread of Ottoman power into adjacent territories in Europe, Asia, and Africa. Was the ottoman system of rule a significant factor in determining the success of Ottoman imperialism?
As in all times throughout history, Empires expand and contract partially due to the other political entities around them. Byzantium and the remnants of the old Roman order had decayed to the point where the more robust Turks could expand their influence, then eventually take over.
The success of the Ottoman empire was very definitely linked to their system of rule, and in particular, as #2 indicates, their religious policy towards the lands that they conquered and took power over. Their decision to leave the Orthodox Church in tact was a shrewd move that clearly indicated their understanding of the fear of those people in lands they were taking over of the Catholic church. Against the wider backdrop of the conflict between Catholicism and Orthodoxy, it was clear that such a policy was greatly attractive and beneficial to the Ottoman Empire.
Another important factor in the spread of the Ottoman empire was their military prowess. No empire became a great power apart from military might. Moreover, when the Ottoman Empire took over Constantinople, we need to realize that this was a very important city in terms of strategic location and symbolic value. It was one of the most important cities in the world and one that directly linked to the Roman world. Moreover, it was in the crossroads of the West and East.
I would say that their system of rule was a significant factor. One aspect of their system of rule was that they left the Orthodox Church intact. This allowed the people of what used to be the Byzantine Empire to accept them fairly easily. They thought being ruled by the Turks (with the Orthodox Church still intact) would be better than being ruled by the Roman Catholics.