Crafting mats should use NO inventory space.

Viblo

They may add more upgrades to bag space later. When the inventory was purposely designed around not being able to hoard every single material you come across in the world, don't expect any changes because it is exactly the way they want it to be by design. And the way it should be for a healthy game. No single person should be able to easily do every craft because then why would anyone ever seek out someone else for crafting? There would be zero point to crafting other than to supply oneself.

Elgarr

The reason they have done this, as well not allowing faster searches through the AH is one of the most laziest ways of trying to create an mmo.
Time sinks.
It absolutely stinks, that someone in there tiny brain,thought it a great idea that the more time people spend doing this, the less time they are getting through content and spending more time paying a monthly sub.
Or the more you will spend upgrading bags, then its a gold sink (and they wonder why they have gold seller problems)

There is no other reason why they have this, because if it isn't this, it's just down right disgusting they haven't let items of crafting materials stack better.

No one will admit to such a lazy thing.

Whoever it was who made this call, read this.

Absolutely disgusted and you should be ashamed, you wouldn't want this in an mmo you played (hence why you know enough don't play) so why make others suffer it.