I am ignoring your point because you are wrong. There is nothing special about Ifrit and Moogle drops - they are lazily itemized trophies. You can have unique effects and still have items be meldable. There are no stats on either set of weapons that are so crazy that they'd suddenly be game breaking if they were also meldable. Future itemization would obviously take meldability into account and could still have unique effects without breaking the game.