Pay for your inventory.

[Darkshade]

They should add one free retainer with the expansion. That way, if you have two, you gain an extra one (free) and the ones that already pay for two retainers (totalizing 5 retainers) would be able to subscribe for 3 extra ones. I think this would solve things a little since I see no reason for you to have more than 5 retainers unless you're an omnicrafter or a collector.

This so much. Every expansion should offer free alternatives to increasing your inventory in some manner. (Gobby Bag Quests in FFXI anyone?)
This is a huge cash grab and is almost as shameful as the cash shop.