This is an interesting one. Many important factors here.

I personally think that when Castro dies, cuban leaf production will slow to a crawl for 2-3 years or so while the US intrusively sets up the government in Cuba. After that comes the privatization of the Cuban cigar companies and their crop which might take another year or so, not to mention a possible oversight committee constructed from the "former" Habanos SA to insure Quality, and enter stage left FDA and Surgeon General's Warnings (latter assuming US territory status).

Now enter the Gold Rush phase where nobody thinks about blending Cuban tobacco into "Domestic" cigars lasting a year and a half or so when quality takes a long back seat to quantity demand. I imagine that about 10 years after Castro dies, the market will stabilize with slightly higher prices and inflation, and finally come back to quality standards, eventually.

Note: I am not claiming any experience in the realm of economics, this is just my two cents.