The Whited Sepulchre opinion on Romney is as follows: Romney has proven that someone with red(neck) state policies can get elected in a blue(blood) state. He has money to burn. He's an ok, if slightly robotic, speaker. He saved the Utah Olympics. He's made a lot of money. Like most Mormons, he works hard.
What is disturbing about this to many of Romney's potential Red State constituents? Well, most of them subscribe to a belief system that claims God took a liking to various Nomadic Tribesmen, all of whom lived in a small corner of what we now know as the Middle East. Not just any regional farm-team god, but THE God chose these Tribesmen as His favorites. THE God didn't just give them some puny little gold plates, he gave his rules to them chipped in stone. God took a personal interest in all of their laws, battles, and dietary habits, and inspired these tribesmen to write a collection of stuff which was kept as an in-house proprietary document for years.
So Mitt Romney has an obvious conflict with many Red-State religious groups (which tend to be more devout than their Blue-State equivalents.) Many commentators are making comparisons to the situation faced by Kennedy because of his Catholicism. Granted, Kennedy was running as a Catholic in a predominantly Protestant nation, but most Protestants understood Catholicism. Protestantism is a Catholic splinter group. Protestants have simply rejected a few Catholic doctrines without adding too many others, except for a delightful acceptance of birth control.