Maybe it should be Reagan, Churchill, Thatcher and Ike on the next mountain!
While I agree that Reagan is the principle figure in stopping the Cold War, Gorbachev set the groundwork at home. Without his efforts within the Soviet Union, the Cold War would still be happening. Imagine if a soviet leader the likes of any of Gorbachev 's predecessors had been in that office.
If we're going to include world leaders then Gorbachev should be a part that monument.
If the monument is only for U.S. leaders, then Reagan should stand alone.
Sounds Good...some may take exception to the Brits...Adm."Swimmer" Kennedy and his Evil Ilk. :/