I'd argue that one of the best ways to deal with the ethnic tensions in the short to medium term, thus allowing for a long term solution, would be to go with a policy of internal economic integration between the different regions of the Empire; particularly via infrastructural development and urbanization/industrialization focused on the Aegean core regions and pro-Ottoman urban-cultural centers. Fundamentally, Arab and Kurdish nationalism as a positive/active force relative to the Ottoman state are weak and fragmented ideologies, and so if not prodded at too much can be kept quiet.
If I could reach down and fiddle with affairs to my contentment, the Empire needs a period of international security, a jump-start of seed capital, and the ends of the Capitulations. Have places like Izmir, Ankara, Mosul, Bursa, ect. given state support to develop light industries that produce goods the Eastern and southern denizens of the Empire would like to buy, while developing raw resource extraction/efficiency of agricultural production in those areas. As the need for labor in the farming sector goes down, movement around the Empire becomes easier, and the need for semi-skilled labor increases, you produce incentives for younger sons from the countryside to get an education and move to settlements in order to get greater access to quality of life goods and higher paying/stable jobs; increasing literacy, the influence of the broader Ottoman identity on the population over the generations, producing prosperity and family connections that discourage separatism, ect.