Simplify it all and just make it so you can store gear to each moggle storage slip to that job.
Example : moogle storage slip01 is war gear only holds 60 slots. You can put in any piece of gear that can hold a warriors piece. If the piece is war/rdm/bst/dnc can still store it , since still shows war as a piece that they can use.
Yes it, does make it so might need to get more pieces of gear for each job, but keep you busy. for each job your playing and or , makes it that need to farm more gear or buy some.
You still keep it the way it is for items that is rare or R/E that you can only hold one them at time in main inventory, but if it in the slip you can hold only one them for EACH job in the slip. So if it a all job item can hold 20 the same thing for all slips.
Stops people that when they need to change jobs , from spending 20min in lower jueno to get there slips. for that job,
Have more then one use for gear that are for sell in the AH, yet can still store it on the slip , just normal, can have some pieces that are random augements not able to store, and the other crazy stuff. , also have some the +1 gears in the AH become rare and not store able on the slip.