I think that people wouldnt call that a compromise simply because while those outfits are fun, thats not what people are asking for ultimately.
Lets go to the extremes then, just for the sake of discussion: What would be the downside to a complete unlock?
The cons is yeah, you will get some players small group of players who will yuk it up to the max and make the most ridiculous glamours. But since we already have the off chance ones (swim wear, pig/chocobo/etc) what would drastically change? Are we honestly expecting we'll start seeing a majority of BLMs wearing PLD gear, and PLDs Running around looking like BRDs, and BRDS decked out in WAR gear like a power metal band? If people have a specific vision of their character in a fantasy world that already allows for a tank to run around in a swimsuit and pig head, why are there restrictions in place. Because realistically, were not even arguing if ti should be a thing or not, but rather where to draw the line at.
In regards to race specific/GC specific/etc, theres no reason why that cant be unlocked. That gear is generally glamour/starter gear and has 0 to do with class recognition (or even race recognition after 20 minutes of play). If were gonna allow people to glamour, then restricting it to race is a really silly position because it doesnt stand for anything after 20 minutes of play. GC glamours would mean more if GCs meant more. But they dont. The choice in GC is arbitrary at this point in the game, outside of a few titles and maybe a mount and a glamour. But we can swap GCs at will now so there isnt anything stopping someone from getting other glamours or even titles.
At the end of the day, its giving players what they want : More creative freedom to design their character. And I would hazard most players arent going to glamour into really trolly looking glamours for their class. If that were the case, wed see more of it now, but its a blue moon when I run into a healer or tank whos wearing a swimsuit into a duty.