I'm very much in favor of adding more content that pertains to particular races. I'd love to get sidequest chains that delve into the backgrounds of each clan of each race.
But I really don't see how racially locked gear appearances can be regarded as a step in that direction. Keeping a rather weak racial distinction that doesn't appear to have any cultural significance, just because we don't have anything else, doesn't seem to me to be valuable enough to be worth restricting people.
How about because cultural significance doesn't really have anything to do with locking them. A Japanese person could wear a kimono when they want to celebrate their cultural heritage, but I (who am not Japanese) could wear one just as well to celebrate my interest in Japanese culture. The outfit is associated with a specific culture in either case, but that doesn't limit who can wear it.
You could substitute the traditional dress of any nation or culture into that scenario and it works just as well. It doesn't make sense for it to only be the members of a culture who would be interested in that culture. That's not how the real world works, and it makes even less sense for Eorzea to work that way, where in many cases you need to go back thousands of years to get to the point where the different races actually lived in different cultures.
So giving outfits some actual cultural significance would be great. But it doesn't follow (or even make sense) that they would be locked to a race on that basis.
So have sidequest chains that delve into the different racial cultures and history, and which reward traditional outfits from that culture. Lore buffs will be delighted. But maybe my Miqo'te would be interested in Raen culture (which kind of makes sense actually as his main job at the moment is Ninja). If so, he might want to wear the traditional Raen outfit as much as the traditional Sunseeker outfit, so let him collect both and wear either.