Honestly, I think these kinds of things should just be a pay-per-month upgrade like retainers. If the data is so taxing on the system, then just have players pay for the storage system via Mog Station. A retainer adds roughly what, 150 slots for a buck. If a buck could get you, I dunno, 10 plates per month that's not bad.

Personally, I don't need more than 1 or 2 for most jobs. Maybe 5-6 for my mains?