They should make (at least some) coil drops "damaged" and you have to take them to a crafter to get them repaired to use them. They'd be untradable, but you'd have a system like materia where the person with it opens a window with the crafter, crafter agrees to fix it, and it's done without the gear actually changing hands. Now you have something for crafters to do end game, and you make sure people still have to run dungeons to obtain the gear in the first place.

You have my contact info, SE. Let me know if you want to give me a job. A corner office, if you'd please.