I definitely understand and respect Elizabeth's comments about her costume and want her to feel as comfortable in the role as possible, so if they were to change the costume to accomodate her wishes then I wouldn't be mad at all. Especially, because Wanda does have a few costumes where she is completely covered up. And since they have foregone the arguably most recognizable aspects of her costumes (headpiece and capes) covering up her cleavage wouldn't be the worst thing.
That being said, I feel like Wanda is a lot of things, but shy about her body and showing off her curves is not one of them. True, it's a comic book trope for most females, but most if not all of Wanda's costumes have ranged from skin-tight to straight up revealing.