I actually wonder if the Russians were actually hold the city. For once, it'd be an exclave. It looks ugly on maps, but that's beside the point. As RGB was just telling me, 1829 is too early for any industrial style cleansing. We're not going to see an Orthodox and Greek Constantinople restored. If anything, I imagine the Russians extracting terms out of the Turks: some boundary changes in the north and possibly in the Caucasus, the Greeks finally gain their independence, and at most perhaps the Danubian Principalities come under Russian protection and tribute. Nationalism in the Balkans didn't yet exist aside from in Greece (which was a totally different situation, with Greece having been in contact with the Enlightenment and it's ideals). In the rest of the Balkans Nationalism was still in the proto-crystalized state. an independent Bulgaria won't spring from this victory, for instance.
Besides, control over Constantinople for the Russians. It was never a practical part of their foreign policy. It was often leveraged for propaganda purposes but I wonder if they actually took the city, they'd keep it. Or if they would even want it. They'd probably simply use it for leverage for other goals and return it. The capture would be a grave loss for the Ottomans... but they aren't going to collapse. Maybe Muhammad Ali could make a gambit to take over the whole empire in the 1830s, and replace the Sultans. But the empire isn't going to collapse and disintegrate. It's not going to collapse because simply, what would replace it?