Just a comment from when I lived in China. In reality, a reime can never control all aspects of life. Once I knew enough Chinese to have deep enough conversations with people, I'd found that as long as we were respectful of Chinese patriotism and did not diss the country per se, and tried to understand their concerns, they were quite open to discussion.
Now let's put this into perspective. Imagine a Chinese coming to Canada and spouting off how evil Canada is and how Quebec should be granted its sovereignty along with all the First Nations, or at least respect their treaties, that we need to change the BNA act to scrap the separate school system, etc. Some Canadians would be highly offended by that. Not surprisingly, many Chinese react the same way to ethnic issues in their countries.
At the same time, if a Chinese came to Canda to criticize these things, some thicker-skinned Canadians would not be offended in the least they may or may not disagree, but even if they disagree, they'd be able to approach it in a controlled intellectual manner rather than just react angrily towards that Chinese. And sure enough, there are Chinese I'd met in China who were the same. Some even agree with granting more freedom to all Chinese, special protection for minority groups, and acknowledge the injustices of the reime. But even they woudl hear nothing of foreign intervention to impose democracy from the outside. Even they would insist that it must come from within, from the Chinese themselves, and all in due time. Very, very few Chinese would support foreign intervention.
Even those I'd met who opposed the reime could still acknowlege benefits of the regime too. One, for instance, insisted the government should gradually grant more freedom over tiem and that the people ought to pressure the government to grant such freedom gradually. I'd witnessed a strike on one occasion in China, and had seen public debates about social policy with open criticism of this or that policy. Granted, it's never directed at the government, but rather at its policies.
Did I feel free in China? Not very. If anything, I felt suffocated in some ways. That said, I certainly did not feel as oppressed as people outside China make it out. Most Chinese woudl rather pur up with some suffocation of freedom for now and gradually open up than have open civil war or economic collapse as had happened in the former USSR.
Looking at it that way, I'd say the best way to force China to open up is simply to open ourselves up to China, to free trade, etc. As a result, as we become increasingly interdependent, it would become increasingly difficult for either country to control its people. Seeing that in Canada the government does not control us that much anyway, it would be an easy pill for our government to swallow, but for the Chinese government it's a tough catch-22: development vs. control.
I don't see why it would be any different for Cuba. The more we open trade etc with Cuba, the more interdependent we'd become, and so the more difficult it owuld be for Cuba to control its people as they are forced to have more freedom to go on business trips, etc.