One of the things I'd recommend PSO2 do to help alleviate the item and data storage issues, is to remove the sweets box system, and make sweets into an affix-like system for pets. Give these "pet affixes" a success rate, and whatnot. This would remove the need for the caramel crusher, and the sweets retrieving items for one. It would also remove the strain on the client/servers for storing sweets box information and sweet compression. It would also allow stacking/higher stacking for sweets.
Another thing I'd recommend is PSO2 removing the "Sub Add" units, or converting them into "Affix Add" fodder items that can be stacked. These "Affix Add" items would work the same as a unit or weapon that has an affix. The affix however would be a single affix, and would be in the item's name. Such as "Stamina Add." These would only come in tier 1 / level 1 affixes.
The next thing I'd like to suggest is a complete overhaul of the Affix System, to be simpler and easier to approach. The system would basically end up mimicking Final Fantasy XIV's Materia system in a sense.
Removing the Complicated Unit/Weapon Fodder for Affixng would be one of my first suggestions for this. Currently, when you want to affix something new/etc. you have to open up the affix menu and select weapons/units to sacrifice. I'd recommend instead adding an "Affix Extraction" system where you can remove affixes and add them to an "Affix Add" item. By default, these would be named "Blank Affix Add," which can be bought at an NPC shop or gotten via Ex-Cubes/Photon Boosters. The Blank Affix Add item would be considered a material. When you open the extraction menu, you select a weapon/unit that has affixes on it, you can select multiple items that have the affix you want to be extracted to increase the chance of success. You can also use a support item, such as the affix success items. After obtaining the necessary "Affix Add" items of your choice, you can then slot them into affix slots for your equipment, which leads us into my next part of this overhaul...
Affix Slots should be fixed / randomized and have empty slots to add affixes to. The current "upslotting" system will be entirely removed. Instead, "Upslotting" will be handled through a new menu called "Slot Drilling." This will add a slot to a piece of equipment. The maximum amount of slots the equipment can have will be determined by the rarity of the equipment. Slot Drilling would have a a couple failure outcomes that could occur:
- Great Failure: Reduces Enhancement Value (-1 to -2) and may reduce the amount of slots by 1.
- Failure: May Reduce Slots by 1.
Adding an affix slot to a piece of equipment with no slots, would be guaranteed. A secondary support item can be designated, such as a "Blank Affix Add" to store the lost slot's affix. This would give players peace of mind when attempting to add more slots while giving them new ways to spend currency items.
Crafted Weapons/Units could have slots added to them on crafting. Adding "Blank Affix Add" as an optional crafting ingredient would allow them to have slots, albeit empty ones. The amount of Blank Affix adds required for extra slots goes up exponentially based on rarity of the crafted equipment and how many slots the crafter wants to add.
If you want to see other inventory adjustments go over to @Princesse-Jen's thread: https://forum.pso2.com/topic/5793/inventory-adjustments/