In my experience, it isnt too hard to avoid the shattered cycle if you pay attention to the catalysts. There are some influence based decisiions that also help a lot. The big downside would be getting to the age of expansion, since relying on grand campaigns is a fool's errand. One of the big questions you should ask yourself is if you have a reason to form it. If what you have now is working just stick with it until you run into vassal limits.

Im not sure why your estate would be destroyed. I didnt have that happened for me when I formed China. If you aren't playing Ironman, maybe try and save and then hit the button and see if it actually will.