I think, and I could be wrong, that the 16 slotter isn't even counted as like, a bag? It's like.. the bank almost. it's just.. space thats there.
i dunno, It's not that big of a deal, but It would be nice if it was upgradable, even if you couldn't upgrade it as an item you know, like a cloth turn in or something
turn in 300 x netherweave and it goes to 18 and so on and so forth.. till it gets to 28. making the top tier requirements cost a fair few of that tailor cloth.
this could be doable through a quest