There has to be physical attraction between two people in order for the relationship to work. But I don't think that you can look at someones physique with a microscope. Unlike a personality, a persons physique can be altered, changed and improved. But what is on the "inside", most likely is going to be the same, or unforunately, may even get worse as the person gets more comfortable with you, and is not on their "best behavior".
I also think that if you are looking for a lasting relationship, you have to look at the total package. There is no such thing as a "perfect person", everyone has flaws.