i'm pretty curious as to some of the reasons for this. For china i know that the concept of the mandate of heaven played a major part, but i'm a bit lost on the other two. I'm only interested really in up to the 16th century so no sengoku
I'm confused by the time period you're asking for. The Warring States period spans 1467 to 1603. Are you asking about pre-Warring States, starting at 1467, or pre-16th century, including the first 50 years of the Warring States?
Between 1336 (founding of Muromachi Bakufu) and 1467 (Onin War) there were 6 to 10 major ikki revolts.