I get what you mean. You are going off how other characters in game see Allison, but I objectively see Allison as very sexy. Is she pretty in the face? She's kinda plain there and I admit Cindy has her beat there.I don't go for my subjective opinion about how hot I find Alison (in that case almost all girls there are 10s), but what the game indicates and tells us. Several characters get far more compliments and attention, Ians and Lenas descriptions and thoughts about their partners is also a good indicator.
Alison never got much attention. She was a nerd and teased about her tits, indicating just having big tits doesn't make you a ten if it doesn't fit with the rest with your body aesthetically.
All she manages to get is a loser like her ex, Jeremy who doesn't have exceeding standards and Ian by players choice.
Hence Axel didn't gave her one look when she introduced herself to him.
But I really don't care how ingame characters feel about Allison I like how she looks. I have always liked tall gorgeous women.
Allison is the female version of tall dark and handsome, only instead of muscles she's has curves as the day as long.
The only thing the game is missing is a female bodybuilder who still looks feminine, although Ivy and Lena both come closer to that than anyone else.
Never was much attracted to Lena though, the weird gray hair and the black cat make her seem like a witch with amnesia who does not know who she is.