> I don't have an opinion on that. Just want to point out that out of the previous 2500 years, China has been unified for only 500 years, and 300 of those 500 years was spent under the yoke of a foreign invader (the Mongols).

This is not true, Mongol rule only lasted for about 100 years.

Han dynasty lasted 400 years. Tang about 300 years, Ming and Qing together lasted about 550 years. All of that adds to about 1250 years of unified times. That did not count Qin or Sui or Northern Song, which are unified that just happened to be short lived.

I don't know where you got your numbers.