I want to like that idea, but the example seems a bit extreme to me. Fighting side by side with melee fighters in coatees and canvas vests just would feel too off lol.

But I do agree that "materia" can lessen the burden and assist people who want to look a certain way and be effective. Say mr haubergeon, crafted from skilled metalworkers, this is a great pick up and go piece of armor. Solid stats, set in stone, not much else to do. But other options, say armor that drops from NMs and the such, could have weaker base stats, look completely different, and have many empty slots for your liking. Then you can cram the materia you want for stats you favor into a piece of armor that you enjoy looking at. It'd be a lot more work, but you'd also potentially end up with a stronger piece that houses your personal style and stats.