This is my fourth attempt - on the first 2, the Ottomans never split up their 45-galley doomfleet, and on the third, they just kept all their troops in the Balkans and, despite my alliance with Poland, just declared on me in 1447. I never stood a chance.
On the fourth attempt,
I parked my fleet in the Marmara and the Ottomans never really came for me in the first war. My problem was that Tunis and Tlemcen kept landing troops in the Morea - at one point they fully occupied it, which did terrible things to my War Exhaustion until I managed to unsiege the region. Likewise, the fact that I occupied Edirne first meant that the Ottomans' war exhaustion went through the roof, and consequently I couldn't take any of Bulgaria in the first war due to it being carpet-sieged. To make up for it I took all of it in the second, and I took the east coast of the Marmara in the third (after this screenshot).
Happily, Corfu defected to me at some point - I'm not even sure when - while the successful conclusion of the Austrians' war against Venice forced them to release Naxos and Crete. The only significant war I'm going to have to fight to regain mastery of the Aegean is the war against Genoa in order to regain Chios. Georgia has also managed to reach genuinely stronk proportions and has taken the entire Caucasus, while Naples escaped its Aragonese PU and is currently allied only to Siena and Ferrara - I will probably either force-vassalise it or kick it apart by 1530 at the latest.
I never tried Byzantium in 1.7, but it doesn't seem like the loss of the extra cores is really a problem, and it's certainly a doable campaign as long as the Ottomans don't keep all their troops in the Balkans and jump you as early as they can - if that happens, you *are* screwed.