I don't see why something like this is a problem. Or Romney's association with RomneyCare. All the candidate has to say is they tried to meet the electorate halfway and give them some centrist policies. As a governor you have to make compromises to govern.
I don't think this kind of thing (i.e., Pawlenty's sharia mortgages) is a problem in the general election
. It is in the primary, though, and precisely because of what you said about governors having to govern -- the Republican base just isn't interested in governing.
Romneycare will be a bigger problem, I think, since it makes it pretty impossible for Romney to articulate his opposition to Obama's health care bill. My inclination is to say this will actually be a bigger problem for him in the general than in the primary, since in the primary all Romney has to say is "I hate Obamacare" to get cheers from the crowd, whereas in the general the crowd will actually want to know what his idea is and how it's better.