There are several reasons I mentioned the stacking items, but it was not to give Ariki a headache.
For more bank space, a new vault could be created, that adds additional inventory space, 50 slots would be nice
Apart from wanting more bank space, it was also thinking of the practical side of things.
Holy Dager, Gwydd has 3 spare inventory slot, Mael has 4 spare inventory slot, so it makes for a lot of running around when turning in this quest, including bringing back the WHoP.
Rung is another odd Quest, he's hard enough to pin down at times, bringing back the robes also fill the inventory. keep in mind that while I do this Quest I can not pick any items from the ground, off corps, that kind of kills the fun.
For me, Questing also means Hunting (when time permits of course), killing beasts and looting, looking for bags etc...
One more, take Crafting, Blacksmithing, like Ardi already mentioned, plates have to strip down to there undies in order create enough inventory space to run the items back and forth from the forge tot he stores.
Just some thoughts.