User blog comment:IamJakuhoRaikoben/Chapter 446: The Land Abandoned By God, Review./@comment-24546844-20150727190228/@comment-24546844-20150728234431

Well, considering that none of the celestial spirits changed at all (correct me if I'm wrong) during the seven years timeskip I don't think Hiro is ever changing the appearence of any of them, but it would be nice.

Actually I guess all the spirits could take an appearence that matches the masters preference like Virgo so if Lucy wanted she coulsd ask him to change his appearence too, but since the start Hiro has gone for something "funny" with all the spirits, so that's not happening either.