The Ottomans being a poor example as their way of managing the biggest part of their empire was through the use of political influence, thus invoking entities that are not defined in the game (most of Ottoman's possessions could not even be considered client states as depicted in game).
Ehh, I always wonder about this line of thought. Exactly which states of the period had the central government exerting more control of territories than say Ottoman Serbia?
After all the writ of Parliament often did not run all that far. Dafoe, for instance, notes that smuggling was rampant from "The Mouth of the Thames to Land's End". Likewise, Parliament's ability to press gang sailors from even places like Bristol was quite limited. And certainly there have been all manner of locals who opted to take matters into their own hands when it came to things like committing acts of war, developing industry (even in defiance of of edicts to the contrary), or even negotiating with rebels.
I mean does anyone thing that the Russians on the Amur were more closely hewing to the Tsar's policies than the folks in Cairo were hewing to those of the Porte? Or that somehow Iceland was checking in with the central government before build a courthouse while Algiers was off following its own industrial policy?
But what about the rebellions and the like? Yeah, totally was not a thing where Venice was sending two independent leaders who could not communicate with each other, on pain of death, because they knew that one guy might do something crazy on his own.
Everyone had governments that were far more varied and diffuse than represented in game. Almost as though no one had invented teleporting ambassadors and magic buttons to spawn fields and population. At the end of the day the Ottomans held formal titles, appointed senior government officials (at least initially), and derived significant income from their far flung territories. Their military forces followed the dictates of the porte, often far more than things like Chinese governors, and they created an elite caste of Turks who ran things for generations.
I can see a strong case to be made that the Ottoman holdings in North Africa and the like were some form of vassal, but I can also see some metrics that would make them far more integrated with the central power than places like Iceland or Lapland. Exactly what counts as too much deviation from central control is ill defined and without nailing it down I would be very leery of gimping the Ottomans just because their weird government structures sound more exotic than the weird government structures of Christendom.