I know what you mean. The "I know it when I see it" argument. I feel that. I understand that.
But, I think one's own preferences get in the way. I don't think hotter necessarily means better. It's slightly different from the "would you rather" question.
Hotness is its own thing. I guess what I'm asking for is like the hotness comparison prototype.
Two given pictures, both very attractive, which one is hotter? The answer being almost universally agreed upon despite similar levels of attractiveness.