Which again - given the growing anti-Ottoman trend occurring in the Arab territories of the time (Syria, Palestine, Mesopotamia circa 1913) - might mean Germany probably gets some nominal control over the most unstable territories (ones furthest away from Instanbul and closest to the British and Persians)
Making a a German-Mesopotamian joint-protectorate of sorts on the cards once petrol is discovered (1917 - 1918 est.)
With German troops are in Baghdad, adventures into Arabia to blunt British meddling could definitely be in the cards.
Here I see no need for any protectorates, indeed the ambitions of the British and French, as well as Russians, never get the traction of war. The Ottoman Empire will suffer from relative poverty and under-investment until the oil begins to flow and wealth blossoms.
Assuming the British support the Arabian tribes in pursuing independence from Ottoman rule and Arab "revolt" in modern Syria, Jordan and Iraq, or the Arab populated region, this timeline I would argue that the Ottomans spend deeper on German arms and rely heavily on German advisors to modernize their forces. In my reading I find the various Arab leaders not at all certain to actually break away and more likely to simply be bought by the Ottomans after being bribed by the British. Without the disruption of the war these tribes are restive but I think basically loyal to the Caliph. The Wahhabists in Arabia are the most likely to accept British support to keep the peninsula independent and oppose the Ottomans but here that likely means they hold the desert but both coasts and more importantly to us the oil fields are open to ottoman rule.
At most I see German advisors used to bolster Ottoman efforts to secure its borders and pacify the Arab populace, and without the three Pashas going extremist under the war I am not convinced they use a heavy hand. This still leaves a lot of room for war to spark off as the British try to exert influence on the peninsula from Kuwait and the Trucial States inland, up from Aden, etc. The battle ground for the tribes is the holy cites in the Hejaz but for Britain it is the area south of Kuwait where oil we know now will be found.
Longer term I am thinking Haifa gets developed as OTL as a deep water port and a pipeline built to transship oil from Mesopotamia to the Med for shipping West. This puts pressure on the Ottomans to build up a fleet, as well as A-H and it sees a lot of tanker traffic up the Adriatic. Germany likely gets serious about a blue-water fleet and this puts them in big competition with the British Med Fleet, not to mention France and Italy. Here I wonder how Italy goes, does it cozy back into the Central Powers or does Britain sell it Persian oil to lure it into the Entente?