I don't see what Yugoslavia has to do with it. Yugoslavia was a very different situation, in that each republic was populated by a different ethnic group, with a history of squabbling.
Slovenia and Croatia were wealthier than the other republics, and they resented the fact that Serbia held the reigns of political and military power in the federation. It is not accidental that these were the first two republics to break away -- and also that they managed to break away successfully. In contrast, Bosnia had a large Serb population, and they weren't about to let go without a fight.
China is different, in that most of the rich provinces have a majority-Chinese population, and most of the poor provinces are also majority-Chinese. The only provinces they're worried about are Xinjiang and Tibet -- and that's an ethnic problem, not an economic problem.
The reason that the Chinese Communist Party is worried about the distribution of wealth is that they don't want a grassroots communist revolution. They know all too well how those things get started ...