Viva la/Nothing new under the sun

Have you heard the news? Castro resigned. I'm not quite so optimistic as to already be planning my humanitarian/beach trip to Cuba--no sunscreen and beach towel in hand. I suspect actually that things will get worse for US-Cuba relations before they get better. But maybe things can get better? As far as Cuba rebuilding itself? (China feels to me right now like a swollen chrysalis, and I wonder if they'll both keep stick to their communist regimes and how that will play out.)
I was talking to some friends about US involvement in the hemisphere/world last night and came back to some troubling and inconclusive conclusions. Like: who the hell do we think we are? The US seems to have its fingers in a lot of pots, and has for more than a century. We've tampered with the governments of most of Central and South America, we're neck-deep in this war in the Middle East (which I know has good reason ostensibly, but we can't pretend we're not in it for the oil, that the democracy rhetoric that we try and throw around is empty justification), we've played with Asia and Eastern Europe and Western.
And it's not to say we're not doing good things too. It's just this meddling problem--we try and help, but eventually have to back out, and a lot of people are left trying to implement programs we've designed (which is always difficult/impossible) and cleaning up our mess. I heard a story on NPR about Cambodia (I think...). The US staged an experiment there: they provided clothing manufacturers with prime contracts and lowered tariffs in exchange for really high standards for workers. In the beginning, it worked great: everyone was content with the products and the workers were some of the most well treated in the world. But then the US preferential treatment expired and the economy took a nose-dive. An experiment? Who do we think we are?
To be a world power, must you interfere with the workings of other nations? Is that part of the package?
Anyway. I'm excited to see how the Fidel-void is filled. And hopefully things will work out the best for the Cubans.