i will add here that given our trade relations with, say vietnam or china, it is clear to me that the ongoing cuban embargo is all about castro. the US (rightly, from some perspectives) will not back down on a failed embargo on a banana republic that 1) allowed soviet troops, with local control of tac nukes to deploy against anticipated US action and 2) has stood up to us 90 miles off our coast since before most americans were born.
once he and his brother are gone, pretty sure the doors begin to open. it is quite crazy to not trade with cuba while we export our manufacturing base to china and buy a ton of oil from venezuela, who in turn gives cuba tens of millions of dollars of free oil.
I would bet a lot would depend on our Cuban expats.