I'd like to see dyes in particular either moved to the currency window, or massively consolidated so that a red dye unlocks all the reds, a blue dye unlocks all the blues, etc. General purpose dyes can be left as-is with the consolidation, but even there we can probably consolidate the pastels, most of the metallics, and have jet/pure be combined into 3 separate options.

FATE rewards and raid rewards can be moved to the currency tab, their only purpose is to be traded anyway, which is what a currency is supposed to be.

Beyond that there's not much more I think needs to be done, Jojoya is right in that part of our inventory woes is self inflicted, and if you don't plan to use something soon, you should sell it. The gil you make there should help buy it back if you really do need it later. My main complaint really is that the game shoves a lot of junk our way, so managing inventories can be a pretty time consuming affair.

When it comes to making dedicated inventories like a tackle box or materials bag, the question to ask is if it actually helps reduce server load to have them. If it turns out that having 10 dedicated bait slots is just as server intensive as 10 general slots, why not have 10 more general slots? I don't do fishing myself, so having 10 more slots overall gives fishers the 10 bait slots and everyone else 10 more dyes to hold onto or whatever. If Square can actually make dedicated inventories worthwhile, so that 50 bait or material slots has just as much server load as 10 more general slots, then yes, I'll happily take a materials bag, tackle box, dye bag, whatever, otherwise, I'd rather they look into consolidating items, being more liberal with the currency window, and not be so ready to fill our bags with junk.