I've been playing a Venice game for months and your AAR was too painful for me to read completely. However, because I actually enjoy pain if it's self-inflicted, I decided to try it out on my own game. To my surprise, it wasn't nearly as bad as in your Venice. I watched as Naxos until the game froze about 50 years later. I only lost 4 provinces in Europe and I still have more than a dozen CoTs. Mexico and the Carribbean were overun with particularist rebels, and China, Arabia, and Japan were in the process of being effectively lost. However India remained fully intact, as was South America and most of Africa. Things that helped was continuity in the provinces, and stationing troops in discontinuous provinces before giving them to the AI since the AI will mostly leave them where they are (the AI clearly doesn't know how to use transports). It is quite frustrating however to see a Venetian doomstack of 44 000 sitting next to a rebel force of 8, and have the doomstack do nothing even after the province defects. I mean what the hell...
This is the game I was playing with:
I'd upload a saved game if anyone could tell me the best way of doing it. Basically, my point is, the disintigration of an empire if given to the AI isn't a sure thing.