I can join in on this, i have never ever seen Ottomans as strong as this. Firstly they + Muscovy won against me (Prussia) and PLU around 1550's, even though Muscovy got badly thrashed.
And now (1570's)they are actually invading and beating a big France (!) + allies all alone. Elan! makes it somewhat even battles, but with alot more troops, 115% disc. and higher tactics than France i have never had a bigger grin on my face ^^.
I am quite fine with it though, seeing now I have 2 endgame countries to have fun with, and they were a monster in that period. Only sad thing is that they never much use it against Europeboth these wars were defensive.
I will just say this, I "play" tons of observer games every patch, even if I just leave it on when I am doing other stuff. Based on that experience I decide what I need to do in my personal games.
Since, probably release, the Ottos have been very high on the priority list, higher even than France, with Austria, Poland/Lith and Russia following up that list (England never really gets off their island except for colonies).
If you get to 1550 with someone like Prussia, and I don't know who you started with, and Muscovy was still a going concern you have not prepped your game well. Even the Ottos, you can ally someone like Genoa if you have to, or Venice, and you get at them that way, and then you beat them down like crazy. You do not let mad dogs get to be 400 lbs beasts, why would you let the Ottos?
Now, if you just want to play a tall game in say Gelre, you are probably fine just keeping France in check, but if you want to play the HRE, you need to take the Ottos out before they take out Serbia, Bosnia and Hungary.