I heard that bitcoin trading in china moved from centralized mega exchanges OKCoin, Huobi and BTCC to more p2p trading.
they are still trading on all those exchanges despite not being able to deposit/withdraw. you can see the high volumes which still exist.
but you are correct that they have moved to a more p2p option.
Sure, it was dictated by the fact that exchanges were not working 100% but now it is hard to tell if all traders will go back.
why won't they come back?
a regulated exchange is 100 times better than an unregulated exchange which nobody is looking into. they can no longer do anything fake, illegal, and they can no longer scam and run away as easy as before.
and more people will trust a regulated place than an unregulated one. just like Forex places.
Instead moon, we could see a reverse situation and Chinese holders will liquidate their long BTC positions.
again i don't see why would they do that, as OP has also pointed out price of bitcoin is extremely low in CNY.
you are saying "traders have waited this long, held their coins and not sold, waited until all the problems are solved with the exchanges, they come back under regulation laws and safer than before and then they sell". i don't know but that doesn't sound like a logical action to me.