Fwiw I’d said motivations, nothing about “hobbies,” so I don’t think you’re actually agreeing with me. 
Especially with that telltale “just”. I’d happily expand the list to include relationships, history, arcs, pretty much anything meaningful you can write around a character.
At the end of the day, what I’m saying is that some CoG characters are shallowly written, but it’s not the genderflip that makes them shallow; and a well-written character doesn’t lose what makes them good if their gender is chosen by the reader.
A whole lot of readers don’t/can’t let go of the metafictional knowledge that they picked the character’s gender, and it colors their experience. Fair enough, but that’s not on the author.
I’d add that a world with less or no gender discrimination doesn’t have to be cheap escapism (though it sometimes is). Discrimination isn’t an inherent consequence of sexual dimorphism.