While I can't be 100% sure about the FFXIV version, since I don't have a character capable of trying it on, Lightning's bottom piece is actually a skort in her own game - it LOOKS like a skirt, but it's actually shorts, as you'd expect from someone who uses a fighting style as acrobatic as hers. When the time rolls around to alter the piece for male use, I really hope they keep that in mind, since males are woefully short of attractive short options.
I would be able to live with 'equal, but different' if the designers could be trusted to actually KEEP things equal. Since they have proven time and time again that they cannot, there's really no acceptable option left other than to unlock everything for every one. Maybe someday they'll be able to prove themselves trustworthy again, but for now they've got to make up for their mistakes.
I mean, unless you're talking about something like a racial piece that would be literally physically impossible for a member of another race to wear due to physical differences, I personally feel that locking any article of clothing is a silly, arbitrary limitation that has no place in a game which allows for customization of your character, but again, as long as those limitations were kept 100%, slavishly equal i wouldn't kick up too much of a fuss.
