RE:China's Communists have in effect slowly but surely given up on Collectivism and state planning as the central role in China's economy.
The trouble with China is that it is very large and diverse, like the Soviet Union was, and thus not really governable by one single central power player. Since Mao, the governance is by a coalition government.
In the past, the coalition agreed on communism, now they don't. But there are still major players that do retain their ideological purity and they are the ones most likely to act aggressively on their beliefs. They are quite capable of causing major ill to the U.S. and Taiwan (which can draw us into a major conflict) over the short haul, subvertly or overtly.
These elements in the Chinese power grid may even have had a hidden hand in some of the al Qaida activities over the last ten years or so. They cannot be dismissed as they are a major threat.
Also, in China, there are two other factors that can cause aggressiveness to rise from that country. Nationalism is replacing communism and it is a dangerous transition stage. Also the country is becoming laden with extra young men who were indulged only children and cannot find women to marry. These men can make the military more aggressive and risk taking.
As for Russia, as they did not actually adopt a true capitalist economy, the citizenry there is not reaping the benefits of one. As a result, there is a rise in belief among the populace there that they made a mistake in abandoning communism, and political candidates that espouse socialism/communism (and keep ties to Western communists) will be more likely to gain power in the future.
Putin, as a result, has back-pedaled a great deal on his initial openness to Western economic and political ideas and ties in order to keep power.
And there are still many in Russia that wish to regain control of their old empire, if only for the many agricultural and mineral resources that were present in those satellite states.