When the west said China political system need a check and balance, what they really meant is that they want a political faction they can use to lobby for the western interest in China. That being said, I still think in the long run, China need to decentralize a bit, for the sake of real check and balance. I always think a nation is like a bus, where the government is the driver, and the rest of us are passengers. We let the driver to drive us to our destination, we could also let the driver to pick the route, but if the driver is heading to wrong direction or even to a cliff, as passengers, we need to be able to correct the driver. If we get thrown out of bus every time we warn the driver, then that bus will surely head into disaster. Sure, they maybe one or two spies in the passenger seats, but still the benefit of being able to criticize the driver outweigh the cost.