Guess what? You don't have to use a medicine cabinet or the unframed, flush wall mount mirrors that are typical in most bathrooms. Add something totally unexpected like these ornate, antiques. Something like this tends to be more functional in a bathroom that is not used a lot like a powder room. See that copper bowl above used for the sink basin- very cool! But note that with copper there are quite a few cleaners and solvents that you cannot use on the copper finish, just fyi.
The smaller size and shape frees up space along that back wall and then you can add more lighting like the sconces in these pics.