I think the difference is that Reagan compromised on legislation to get key points passed (and to expose the RATS for who they really are). Romney compromised his principles to get elected.
Politics is a game of compromise. We can assign reasons to the whys to fit our own personal prejudices, but that doesn’t change the fact that all politicians compromise. I am sure Huckabee, Thompson, McCain, even Mr. Hunter have all compromised during their long political careers. What we must look at is what was accomplished by the compromises made. If we got better than 50% of what we wanted then we won and in politics as in negotiations and war that is the name of the game.