I disagree. Adding storage slips WOULD free up tons of inventory. Especially now that delve and skirmish2 gear is so highly prized.
The problem with storage slips and the new content is the augments... when it's something like empyrean or relic armor... it's all really simple (and the bane of ppl who don't care enough to do the xp magian trial for the relic+2) when the augment is static... there's no problem with storing an augmented item...
But due to the customizability of the new gear... aside from like the bayld gear... a storage slip just can't work... Unless, of course, it's only for unaugmented items.... which wouldn't be good... or the bayld gear slip is for only augmented items...
the random augments for skirmish gear and the tiers of augments for delve gear just don't work with the way storage slips work.