Why would the fact that China is basically controlling mining do anything to Bitcoin?
The whole concept of bitcoin was based around decentralisation.
If China controlls a large % of the hash power then it would only take the collaboration of a few to hit the dreaded 51% control point
China owns over 80% from the mining and the trading market as well. China owns over 95% from BTC transactions too.
The centralization is a reality.
https://blockchain.info/pools?show_adv=no
http://bitcoincharts.com/charts/volumepie/
Even if China controlls 80% of the mining power that doesn't mean that we should fear a 51% attack. Do you actually think that the guys who control mining, being Chinese or not want a 51% attack??? of course not, otherwise their investment would be worth 0....