I agree with you that if we ever have another mainland China leg, it needs to be somewhere new. I actually don't want to see China for at least another 6-7ish seasons if they are just going to go to the same cities. Having a 7 season break was nice, now they just need to learn how to do that for France, Germany, and Italy (especially the first).
We know a couple of location for Hong Kong in 37, and the location look cool, so I don't think the leg will be bad, but it gets boring to go to the same cities over and over again.