With the current situation, the Chinese ban on mining, and the fact that the difficulty raised last time, it is fair to draw that the difficulty will drop.
What will be the consequence for the BTC value?
My guess is that it will raise, because of that. The market should take this in account in advance.
https://btc.com/stats/diff
If China ban bitcoin mining, the price of bitcoin and all other cryptocurrencies will reduce but bitcoin will always survive. China can not even ban mining, it is not possible to ban what is feeding thousands or millions of people. It will have negative effect on some industry in China like the mining hardware manufacturing companies and few others.