It isn't so much about putting President Reagan's image on money (paper or coin), but what the Reagan family wants. Despite being the finest president of my generation, the wishes of the family are the primary consideration.
Nancy spoke against the idea that was floating around not long ago of putting Reagan on the dime, saying that Roosevelt had been on it for so long and should remain. She may well feel the same about other coins or currency. If his family doesn't like the idea, then out of respect I would oppose it, too.