The problem of sexism is that it rarely takes the form of overt discrimination that most have learned to easily recognize but more often takes the form of an institutional bias that favors men over women.
it is for this reason that most will recognize allowing Wonder Woman to be secretary but refusing her membership to the JLA as sexism but fewer will recognize other attempts to "legitimize" the character as sexism.
Notions that Wonder Woman cannot dress as a woman, i.e. wear a skirt or tights, if she is to be "taken seriously," as if she can only be powerful in pants; that Wonder Woman must be similar in stature to Superman if she is to be similar to him in strength, as if her magical strength has anything to do with her height or her muscles; or that Wonder Woman must be a demigod if she is to be equal to Batman, as if being a princess, ambassador, and superhero is not enough.
When writers propose changes like those listed above, they demonstrate that they do not understand the character or what she represents: and that is the reason Wonder Woman comics do not sell well; instead of understanding and embracing the character, writers attempt to explain her away or change her to appeal to the fickle attitudes of ever-changing demographics, writing her as if she is Buffy, Xena, or a popular male character, the success of whom they are trying to replicate.
Perhaps if writers stopped pitching everything and the kitchen sink at the character and seeing what sticks and focused on strong, feminist stories, they would sell more Wonder Woman comics.