An orderly rebalancing will be good for the world on average and a disorderly one bad.
The same is true about the effect of a Chinese slowdown on social conditions. People do not generally care about GDP growth rates. They care about their own income growth relative to their expectations. Rebalancing in China means by definition that Chinese household income growth will outpace GDP growth, after many years of the opposite. A best-case orderly rebalancing should result in little change in the growth of household income, even as GDP growth drops sharply. This for example is what happened in Japan from 1990 to 2010, when GDP growth dropped close to zero but household income grew at nearly 2%.
A disorderly rebalancing, however, could result in negative growth in both GDP and household income, with the former dropping more than the latter. This, for example, is what happened in the US in the 1930-33 period – with GDP dropping by around 35% and household income dropping by around 19%. In the case of China, in other words, while elites will suffer in both scenarios, in the former case there is no reason for popular discontent.