So now we have Ephemeral Moogles that happily store crystals for us, and I love them. They are my best friends.
However, sometimes I feel like I'm being a bother whenever I have to keep pestering the little guy to return crystals to me, because I'm too lazy to carry them in my own inventory (and there are thousands of items in Vana'diel that clog up my inventory constantly doesn't help either).
So, how about Re-usable Crystals, courtesy of the Ephemeral Moogle?
Please, give me a moment to explain.
Once you attain Level 60 in any craft, perhaps a Moogle (or any Ephemeral Moogle) gives you a quest. It should be crystal-related, and not ridiculously difficult or expensive, but some fun little quest to do.
Once you do this quest, you can then request a special crystal (there would be 8 of them -- one for each element) from him. He will charge 500-1000 Crystals for this crystal (using the crystals you have stored on him) and he will give you this crystal (which is Rare/EX and not sellable to vendors).
Said crystal is a usable item that is not consumed, perhaps make it an item you can equip if there's no way in-engine to do that yet.
Either way, this crystal functions just like a normal synthesis crystal, but with a twist: instead of being consumed, it consumes crystals you have stored on the Ephemeral Moogle automatically, without you having to withdraw crystals. So, if you get, say, the Wind version of this crystal and you have 1,000 Wind Crystals stored on the Ephemeral Moogle, you can use this crystal 1,000 times without having to clutter your inventory or ask the Moogle to hand you crystals.