The embargo has created a dearth of medical supplies & knowledge, has negatively impacted nutrition, lack of resources, lack of tourism dollars, and provides a bogeyman for the regime to blame for all its ails. It has helped repress and impoverish the people more than anything else. The United Nations General Assembly has passed a resolution every year since 1992 opposing it.
It's possible that, like China, the oppressive effects of Communism could have been lessened (even if just a little) under the benefits of trade with a Capitalist democracy. Medical crises would have been dealt with quicker, and they would have had more cash on hand from tourism to invest in agriculture (or at the very least, import more food).
And you may feel differently about this, but I think the ban on travel really sucked ass for Cuban families who couldn't visit their relatives, and the bans on transfer of money to family members in Cuba. But that's not really a regime thing, that was just the US being dicks.