He's the de jure head of state. The de facto rulers of China are the "princeling" descendants of revolution-era party leaders (http://en.wikipedia.org/wiki/Princelings).
He is certainly one of them, and perhaps the most influential, but he is certainly not powerful enough to be "the ruler".
He is certainly one of them, and perhaps the most influential, but he is certainly not powerful enough to be "the ruler".