You are right, it has nothing to do with him being Mormon, it has to do with no charisma. He's like wallpaper. Good looking wallpaper, but flat and bland and unexciting. You can't be president in this country if you don't have that inexplicable something that draws people to you.
Mitt has all the moves, phony smile and personality of a crooked used-car salesman, besides having flip-flopped on every issue.