I never had big issue for weather avoidance in China airspace but in some airways you can only dodge the weather on one side which can be quite frustrating. They will happily make you fly 100 miles left of track when only 10 miles right would be enough but due to the tension with Taiwan or Military activities ... “CAN NOT!” Not ATC fault, they just follow orders.
Some ATC like Guangzhou have weather radar and will vector you around the weather without asking your opinion.