Personally I love the GW2 system. Infinite dyes, easy unlocks and outfit making at any point in time (though I kinda wish I could save outfits, couldn't last time I played) .
But saying this is "easy" or can be "copy pasted" is a falsehood. The system they've made needs to be entirely reworked from foundations up. From the way appearance is linked to our gear to the way inventory is done. Your proposed solution is game changing, or rather REQUIRES game changing rewriting of the way the entire thing works.
Just keep that in mind when wondering why they dont "just" do things.