Barring Chinese students from foreign universities creates secondary problems. Although it might make sense to some readers of Sinocism, it is a hard sell to a domestic audience.

Universities are increasingly dependent on foreign students for income, so enacting a policy which for a lot of universities would have a real impact on their revenue will upset both staff and students, who will likely see program cuts as a result. At the same time, elites who by and large have fond memories of their own university years may see it as an attack on some of their cherished institutions, and an unnecessary narrowing of the sort of mind-expanding experience university is purported to be - not just for the foreign students, but the domestic students who gain from interacting with them.

Personally I prefer the idea of targeting party members more directly. I do know that a lot of not especially ideological folks join the party just to get ahead in Chinese society, but that's still an explicit decision to support the structures that are being used to oppress dissidents and minorities inside China. It's a calculated decision, but if it's a decision that came with real international consequences (like travel restrictions), perhaps people might think twice about it. Or - having joined the party - they might even feel more inclined to leverage their position of privilege to affect real change. Well, assuming they aren't outnumbered by the members who don't at all care about what they can do in foreign countries.

But, this is all a bit hypothetical. In practice I am not sure that there is much that other countries to do to change CCP policy or weaken the Xi administration. The party as a whole still seems fairly ideologically motivated to me, and willing to put the Chinese people through a lot of pain to achieve their goals. I am not sure foreign countries have enough leverage to make a difference at this point.