I think that one solution might be to add the Mog House system from XI to XIV. They could call it Apartment Wards or something similar. It could have a base storage/bank + storage amount based on furnishings within it. This would also allow them to introduce a delivery/mail system for items. It would also give crafters something else to make.

They could also separate your inventory into several groupings. Weapons/Tools, Consumables, Crystals, Crafting Ingredients, etc.