As long as you put it on a glamour plate, you can remove the piece and use it as normal. Just if you overwrite it, you will need to re-add it to the dresser and do it again. Though, you will lose any materia melded to it.
Keep in mind, they also made this with the idea of being a currency sink.
Given the prices you have to pay over for there for applying said transmogs these days ...
https://i.redd.it/yee9gor9c0961.jpg
Are you sure about that?
Entirely fine. Leveling gear is so easy and cheap to acquire that it's not worth the effort keeping it around for something I'm possibly going to do in the distant future. Also, I'm not even half full in most categories of my armoury chest, so I can just keep equippable gear there and dedicate the glamour dresser for glamours.
Can I also edit other items on the plate, as long as I don't overwrite that one?
Great, I'll try that the next time I need a glamour like that. Currently the only such item is my crafter coat, and I don't want to have to pentameld that again.
I am at 250/400 on my main character. I don't see anything wrong with the current system.