hmmm, I think you can find a few hundred million former prisoners of communism in the East Bloc that are pretty happy the US was "presumptuous and interventionist" during the Cold War.
1) The socialist governments in eastern Europe were based on the imposition of military power by the Soviet Union in the aftermath of World War II and were sustained in crises by Soviet military repression of popular resistance.
Like it or not, Cuba's revolution was a completely domestic creation which has never depended on foreign forces to maintain its authority.
2) Freedom in eastern Europe happened when Gorbachev made clear Soviet troops would no longer maintain in power unpopular regimes.
3) There never was a US travel or economic embargo against eastern Europe. A general case could be made that the transition to western style democracy went most smoothly in societies that had been most open to normal interaction with the rest of Europe and the US. (Miami hard liners were embarrassed several years ago when a conference of eastern European diplomats told them the embargo was counterproductive to encouraging internal change.)
4) The models for real change in Cuba are most likely to be found in other countries with indigenous socialist revolutions like China and Vietnam. Russia itself in effect is reverting to its own cultural and historical view of democracy, even absent the leading role of a communist party. While Vietnam and China have systematic political and human rights problems from the view of the US, Canada and Western Europe, individual freedom has increased substantially in both countries since the US ended its embargo and normalized relations.
5) Pressure from the US for Cuba to become more democratic in our terms carries the burden not only of our interventionist role over the past fifty years, but also of the unpleasant history of the prior sixty years.
6) Anyone who has visited Cuba knows that much of the population wants more individual freedom to initiate private business ventures, to travel internationally and to speak more openly about social and economic problems. The biggest obstacle to that is not the Communist Party of Cuba, many of whose members would agree with these goals. It is the threat of well funded intervention by the US and by the old guard in Miami.
7) Those who argue that Fidel and Raul depend on US hostility and the embargo to justify authoritarian rule logically should be in the forefront of the campaign to end travel restrictions and the embargo. The fact that they take the contrary position suggests their motives are either embittered revenge, or knowledge that the only way they can hope to regain power is by societal collapse, i.e. piggybacking on US "humanitarian intervention/peacekeeping" forces.
8) I sometimes wonder whether there is a more pedestrian motive at work. Presumably no interests in Miami would be as damaged by the end of the embargo as the Fanjul family and those who benefit from Bacardi's domination of the US rum market. Imagine the effect on its market share if not only Havana Club but Cuba's many other fine rums became freely available here.