I just played a Ottomans game going for the Sultan of Rum. The first wars go well, I take all my cores, vassalize Bosnia, Serbia and Wallachia and turn to the Mameluks. My troops arrive at the border at the 27th of november where I decide to wait for the 1st of december to dow and go for their troops before they get their moral up. At the 29th of november my King dies gaining me 12 years of regency council since my heir was just 2 years old...
Still I played on, managed to take quite some lands and even prepared Naples to get annexed in 1550 to get me going for Rome. So far I really managed to keep the coalitions/AE under control, Austria beeing the only western power in a coalition against me (because of my war in soutern Italy) along with Persia and 4 province Ethiopia. I had 0 AE with the eastern powers, so I decide to go for Kazan to release the Golden Horde as my next vassal for expansion into Russia. A short war later I have 100% warscore against Kazan, relase the Golden Horde and still have about 30% warscore left. So I look around and find that lovely province of Lower Don, sunni, basetax of 3 and I even have a claim on it. So I'm like "what bad could it do" and take it in the peace deal.
Some days later Russia decides that it really really is outraged now and enters the coalition against me. Another week later Lithaunia joins them along with Poland who is under a PU with them. To top it off Hungary not only joins the Coalition as well but also goes ahead and declares war on me. So in the end, half the world was coming for me just because I took one single worthless province somewhere in the steppes... well, it was the end to that game.