Let me add some arguments why not having a seperate crafting material stash (think Guild Wars 2) is just stupid, a waste of time and actually having that kind of stash is NOT dumbing down anything.
I want to play FF 14 ARR the ROLE PLAYING GAME, I do not want to play FF 14 ARR's 'Inventory management let's-frustrate-the-player' subgame.

The crafting part of the game IS about making 'interesting decisions' about ... well ... CRAFTING ... not about where I have put my crafting materials and not about moving materials around to and from my backpack using retainers that are only available in certain area's nowhere close to the crafting area's. Retainers are there to buy and sell stuff, not to be used as storage space because we simply do not have anything better at the moment.