To me she's one of the very few AV stars that manages to come over as sexy and cute at the same time. Sure being cute can be sexy but to me usually the cuter they look the less sexy they become in my eyes. Jessica is a wonderful exception to that rule.
I believe a fair amount of her cute looks comes from her baby fat, can't help but wonder how sexy she would be without it. Although it's one of her trademark assets I firmly believe if that happens what she looses in cuteness she will gain sexiness in equal measure.
I'd totally understand some people would hate to see it happen as that's part of her charm but to me sexy > cuteness any day. Take Akari Asahina for example, I like her looks from her early days but abso-fucking-luteley love her after she lost her baby fat. I see it as a coming of age thing. Again, I know some people will disagree this is just my view on the matter.