Desynthesis? Do you want it?

In a way we have this with Desynthing into Materia (Convert -> Materia). You then can get the 'essence' of the item (if not some related crafting materials).

Ive always thought we should have a new crafting class dedicated to this

give people something new to work with

There seems to be a good bit of opposition to this idea, but personally I've thought about it and would like it. When out in the field and you get something, like a linen cap or gown, it would be nice to be able to 'break' it down and either resell the materials themselves or give the mats over to LS mates to be used in other crafts. Instead you're left with other options, sell it, meld it or convert it. All fine choices in their own, but I still like the idea.