China is politically fracturous at the present time. My gut feel is, however, that China will in become cohesive in the longer term . Generational (political) change must of course happen first. Educated dotcomers will eventually take over the reigns and they will hold different views and values to current Politburo members. The strange thing is that current powerbrokers in China maintain an iron fist with one hand while also setting the stage for future change and adaptation with the other hand.

My best and most optimistic guess of what may emerge is a more cohesive version of an EU styled confederation with the current (Communist styled hierarchy) managing stuff like foreign relations, trade, defence, central treasury and some legislative areas. The Provinces are likely to grow their autonomy from the Hong Kong model (not withstanding some of the rough edges in the current version).
Of course, the benefits of belonging to such a confederation would first need to be perceived, by ordinary people from Lhasa to Beijing to (dare I say ) Taipei as greatly exceeding the costs.