I will probably only level Reaper and maybe just maybe play it if it has a lit rotation.
Wait that's not the topic?

Oh, poor inventory management? Listen boy, with friends we made a challenge. Who could shave the most out of their glamour dressing, retainers and inventory. That was before Zadnor.
We went from 400 to under 80 slots taken for the glamour dressing.
Inventory was shaved by half, apart for the weapons armory, all armor and accessories went under 10 slots taken. I'll have to shave again as I'm done with Zadnor.
All retainers were cleaned and one has 100 slots takens.

We figured that we were not using 80% of our inventory. There is no need for more glamour plate, I have all of them filled but only use 4-5 of them. We're not playing every jobs, I haven't touched Ninja, BLM, SMN, RDM, MNK, BRD and DNC since I leveled them to 80.

In short: Manage your inventory in a better way, it's not SQEX fault if you are stacking unused items you think you'll use later.