Byzantine Empire and fun are not two things that I associate together
Heh. I don't much enjoy the endless incremental wars that are required to reconstitute it—especially if ends up distracting one from other goals (colonisation, etc).
But I think Salik's got the right approach in tackling it near the end-game. By then you should have a tech advantage on the Ottomans and it will be much less of a manpower sinkhole than trying to take them on in the early game.