Not nearly as much of a hurdle as the man himself has become.
You know this is a VERY common perception among FREEPERS; yet the polls are even more telling on this:
From the article: He pointed to a recent Wall Street Journal/NBC News poll that shows less than 50 percent of those surveyed said they would be comfortable with a Mormon running for president.
Think about it. 48% say they wouldn't vote for a Mormon. Another 6% are undecided.
Do you really think that you could find a 48% block of voters who thought, "Romney is too RINO...Romney is too liberal...or Romney is too waffly"? Really?
For the liberals, nobody's "too" liberal for them.
[So you'd already eliminate almost 1/3rd of your potential "pool" for a Romney's too (fill-in-the-blank) considerations.]
True GOP conservatives might only be 20-25% of the voter pie. Of them, a decent chunk might be willing to consider a vote for Romney. In fact, Mormons are 2% of the population and are probably 3% of the GOP. You can count on 2.5 - 2.75% of the GOP -- Mormon -- would vote for Romney!
So if you could come up with 15% of the voter pie -- GOP conservatives -- who think Romney's too whatever...you'd then have to comb for 1/3rd of the voter pie amongst moderates & independents & more conservative Democrats to agree with you that Romney's biggest hurdle is himself.
I don't think these 3 groups are well-informed enough 'bout Romney's waffles, liberalness, & pro-abortion stances -- or care enough about them -- to bring this key consideration to a high radar concern level for about half of the voting populace.