Apple already does ban apps on political grounds, even pretty innocuous just-the-facts type apps:

https://motherboard.vice.com/en_us/article/538kan/apple-just...

And yes, I think you are likely right: we will see apps banned at the behest of the Chinese government, given the size of their market. (North Korea, perhaps not.)

Apple painted themselves into this corner when they decided to become the gatekeeper of what iPhone users are allowed to install.