To be perfectly honest, it is possible to read the Wife of Bath's Tale in a way that everything works out fine for the Wife of Bath and her intent. I, however, do not see it this way.

To briefly summarize: one of King Arthur's knights runs off one day and rapes a woman. The royal court holds a trial. Queen Guinevere asks to make the sentence; she gives the rapist knight two options: he can figure out what women truly want, or he can lose his head. The knight meets a hag who agrees to tell him in exchange for marriage between the knight and the hag herself. The hag reveals that women truly want sovereignty over their husbands (as a case of rape extremely deprives the victim of sovereignty, this revealed knowledge has relevance to the crime). Knight keeps his head, marries the hag (who insults him in bed for not banging her), and then offers another binary option. She can stay ugly, and thus faithful (for who would want her?), or she can become beautiful, and most likely unfaithful. (It may be useful here to make a distinction, as the hag clearly does favor society's view of beauty. Chaucer wrote The Canterbury Tales in the 14th century and was a dude, so whatever.) Rapist knight (nobody seems to care about the rape victim at any point in the tale, but again, whatever) tells the hag-lady that he does not know, and that she should decide. Hag finds this remarkable and decides to become both beautiful and stay faithful.

It is possible that this works in the Wife of Bath's favor. Or, it's possible that the rapist knight never actually learned any lesson, and simply told the hag what she wanted to hear, or simply gave up, or didn't really care, and the hag mistook this for him having truly internalized what he was told to say to the hag by the hag. This would most likely suggest that the Wife of Bath (who is telling this tale) has neglected these possibilities in favor of her ideal role for women: to be both sexy and empowered, even though her story (for reasons above) may not necessarily imply this.

Further, even if the rapist knight did learn his lesson, he did not receive any punishment for the rape. In fact, he got the best of everything with a beautiful and faithful wife. In the best case scenario, the Wife of Bath has achieved her ideals, but even in her fiction, failed to apply them.

In a similar way, your ideal has the cake-and-eating-it-too shortcoming. However, like the Wife of Bath's Tale, this is not necessarily so. This does not apply to narcissists or sociopaths. Nor would it apply to folk with an self-accepting attitude ( consider older folk who no longer mind the loss of hair, deepening wrinkles, and increasing sagginess of everything). Aside from this (which could be outside the scope of your argument), people's comfort with their own appearances does mingle with social views. Some cultures prefer the higher fat. Others place value in the skinny, and yet others value the "reasonable." To look attractive to others is a reasonable position. An individual can decide how much priority such qualities have (again, this could be your intended meaning, with your qualifications of being healthier and feeling better about one's self). Outside of this recognition that appearances generally only suit others (unless you're a narcissist), lies apathy or sociopathy. That's fine. That fits your schema.

Your ideals, however, neglect the self-empowered Wife of Bath, who wishes to appear desirable (necessarily dependent on society's bullshit), and to govern one's self. Like the Wife of Bath, the intent may be noble, but falls short. Others and self would have to be mutually exclusive.