In the case of Japanese media including anime, manga and especially their video games like Smash, the societal impact of choosing to NOT listen to people that throw fits over attractive female character creates artistic freedom.
Encouraging character designs that are also perfectly realistic, normal and healthy in body is arguably something positive. More often than not, the people that take the greatest issue with this seem to be American women that don't play or buy video games anyway and ergo are not customers. Not accounting for the fact that unlike Japan, the reality and societal norm of America is to be a diabetic overweight with poor eating habits that gets no exercise.
I shall review that post in steps:
1: 'Attractive' is not a well-defined word here. What do I mean? A word is well-defined if anyone can learn the definition by reference, those who have learned the definition will always know what you mean, the word always means the same thing (hence the 'by reference' bit), and its (the definition's) constituent words are also well-defined (this is a recursion component, and so I can understand if you wish this one to be omitted). Since people are raised in a variety of cultures, circumstances, conditions of exposure, etc., it would be impossible for them to learn the definition of 'attractive' as used above. That is in one instance (a reference), someone may behold another who is called 'attractive', for argument's sake. In another instance, the previous reference says nothing about whether this person should be considered attractive. Perhaps someone would like to explain with descriptions such as "he/she has blonde hair...' but then that would lead to the consistency problem prohibited by the meaning of 'well-defined' above since (let us face it), we may see two different people with contrasting qualities, and still call them 'attractive.'
2: '...Creates artistic freedom.' implies that by refusing to listen to someone (a passive condition), it is possible for one's liberty of expression to be made accessible (an active condition) by those who promote a practice in disregard for another person(s) views, even if this person(s) is 'throwing a fit.' Are you actively doing something by passively doing something else?
3. Is Smash Bros. specifically "encouraging character designs that are also perfectly realistic, normal, and healthy?" I could accept this argument if we were discussing Wii Fit Trainer's origin, but this is a fighting game of a completely different subject matter. Besides, are you going to promote "perfectly realistic, normal, and healthy" character designs for Zero Suit Samus side-by-side with an unrealistic,abnormal, fat human named Wario?
4: Well, let us put the matter of "American women that don't play or buy video games and ergo are not consumers" this way... Let us say YOU satisfy criterion x, but not y. Now suppose that the majority of video games on the market suggest that people who satisfy x must also satisfy y in order to be 'attractive,' as used before. That automatically means YOU are not attractive, by the supposed standards. The translation: Let x= 'woman' and let y= 'blonde hair,' or 'slender figure,' or, 'toned muscles,' ... should make it clear that women (or any group pressured to conformity), American or not, have a valid reason to dislike a commercialized representation of people satisfying x. Another thing... Do they have to be consumers to voice their complaints about a matter of great concern to them?
5. I cannot actually address the verity of the last sentence of your post since I do not know the "societal norm" of Japan, though empirically speaking, I might agree with you on America (cautiously). However, I have no qualms with pointing out that again, x= ' typical American body,' and y= 'typical Japanese body (as asserted).'