Be honest with me here, who needs more than 25 slots for your Key Items at any one given time? And if you do, it poses the question in why you aren't managing your Key Item space efficiently.

People are always calling for more inventory space, and we keep getting the reply that extra inventory space would tax the servers too much, and yet we're sitting on a potential extra 50 inventory spaces because they're going to waste being gated behind Key Items.

If you feel like it, there could be 25 Key Item slots next to your crystals, your bait box for fishers could be another of these 25 slot allocations, thus reducing the inventory clutter by assigning a bait type to the "box" and any excess remaining in inventory, and it means we have 25 extra slots for the player. After all, if retainers can use up all of the 175 slots, why can't players at least have 125, or even 150 spaces?