From what I understand very few of the American-Cubans actually plan to move back to Cuba. The land has basically been ruined by Tobacco and Sugar Cane plantations. Not to mention that stolen property-assets have not been kept up. If Cubans on the island sense that the Castro regime is losing control, many may flee since they would not have to worry about the Cuban authorities trying to stop them. If the U.S. experiences a mass influx of Cubans at the same time we have basically had our borders open to central America, it could cause quite the refugee problem.
There are many, many very wealthy Cuban Americans who fully intend to "capitalize" on the death of a communist Cuba. I wonder how they will be accepted by the Cubans...