I think what a big dick represents that smaller dicks don't is that a big dick is raw 'power'. Women are instinctively drawn to dicks but many of us guys have noticed that it's the big dicks that women actually rave over the sight of. A lot of guys, and many women, usually white women, side step this by going on and on about oral, but it doesn't really address the issue since penis power is something guys can have exclusively but oral is something women could do to women. Telling men that provided he is good at oral it doesn't matter what size the penis is may be handing him some power but it's not a manly power to many of us guys. For afterall, a woman can perform oral on a woman. The penis is exclusive to guys, and the more power he wields with it the better he likes it because of the way women react, and not only the way women react at the sight of it, but also during intercourse. It's illogical though to want so much visual power that it will result in a reduction of intercourse power, which is the case with a Mandingo size dick where the energy used with it must usually be kept on low to medium, not to mention it's probably not going to go all the way the way in. Almost all women express a love of thick dicks, even women who claim size makes no difference will often admit that they only meant length when it's brought up that they didn't mention girth in their size doesn't matter claim. Some women who aren't wanting to admit to penis power will sidestep it by only bringing up length, saying length doesn't matter or that they prefer average length. There are women who prefer average girth but they are vastly outnumbered by women who prefer thick or at least some extra thickness. White women and black women both love extra thickness. When it comes to length preferences there is some differences in general between stated preferences, black women tend to prefer about 1 to 2 inches more length as ideal.
I totally agree with you about some women claiming oral sex from a man can offset a smaller penis. I like oral very much, and have never stopped a guy from performing it on me. But in any sex encouter I have, I ultimately want the guy deep inside me, and I want what he puts inside me to be fairly big. Both length and girth are important to me, and not necessarily one over the other. But whether a guy has uncommon length or uncommon girth, or both, the sex I most enjoy is when I take all of a guy who usually cannot find a gal that can take him all. When that happens, the guy usually gets so excited that it gets me super excited, and that always leads to a very intense, long orgasm. don't know why, just know it does.