While I have not thought hard about U.S. policy toward Cuba, I have friends who do. The below comes from a former government official with long experience in the region. What he says does not give much reason to welcome the normalization of relations with Havana:
The Cuban government runs one of the most efficient and important intelligence organizations in the Western Hemisphere. For decades the Cuban government has run intelligence agents in the U.S. Department of State and Department of Defense, Defense Intelligence Agency and other U.S. government agencies. They maintain an extensive organization of academic, political operatives and agents of influence throughout the United States. Today they succeeded in their long term goal of freeing the Cuban Five (now three) and upgrading U.S. diplomatic relations and access.
Today President Obama released the three Cubans convicted of spying in the United States for Alan Gross, a USAID subcontractor. Gross had been convicted by a Cuban court of supplying Internet and communications devices to the Jewish community of Cuba for a “Democracy Project” on behalf of USAID. President Obama has promised more diplomatic benefits for the Cuban government in the very near future.
Havana has succeeded beyond its wildest dreams with the help of President Obama. He has reversed five decades of successful U.S. policy for virtually nothing. The desperation of the Obama administration’s foreign policy will be studied and exploited by Iran, North Korea and many other adversaries, looking to take advantage of a decaying Presidency in its final years in office.