Meh, who needs Gaston when you've got good ole Xaldin and Belle elbowing him. While I don't think it's at all necessary to return to it, Beast Castle could always return. Remember how Jack Sparrow got cursed again during the second visit to Port Royal in KH2? Same thing could happen to Beast by some KH nonsense. I hope that's not the case though. Let him and Belle be happy, they've earned it.