I've got a few ideas,
1. crafting bags - materials for said craft go into the bag to save bag space
2. more retainers - 2 more should do it
3. if not more retainers allow us to use unused character slots we're not using to make into retainers I mean some of us pay for the 8 character slots and only use say 2. Would be nice if we could use the other 6 slots as retainers, this would also increase your capital per month as people would be paying for the 8 character slots to make more retainers basically.