In a survival horror game, inventory management is part of gameplay because if you lug around several thousand things, its not really about survival and having access to so many items such as first aids often gets rid of any horror also. Inventory management forces the player to make tough decisions, such as deciding between grabbing a healing item, but having to leave behind ammo, or not having room to pick up more ammo later. When getting a key item might mean that for the time being they cannot carry as many supplies, making the game harder for a time.

In MMOs, the only game that comes to mind in which inventory management is an important part of gameplay is Runescape, since bringing food is one of the only ways to effectively heal yourself during combat. If you could bring even 5 more inventory slots of food would mean you have more effective HP, making encounters much more manageable or time spent farming much longer, so changes in inventory for that game comes with HUGE consequences for the rest of the game.

In FFXIV, the inventory management "gameplay" you are asking to keep is running to a retainer in a city, dropping special currency off or destroying it. That is not engaging gameplay, hell I'd even argue its not gameplay at all. You can't trade them, you can't sell them to a vendor, they just sit in your inventory until you have enough to actually use them. They are exactly the same as older Beast Tribe currency, the only difference is where you get them and thats hardly a reason to keep them in your inventory. They did it for Beast Tribe stuff, it makes no sense to not do the same with totems and the such. Anyone against it on the basis of a "Inventory management gameplay experience" should go crumple up paper into balls and throw them in the trash for a few hours if it means so much to them.