It's not that simple.
There was a
dev post a while ago outlining some of the issues they have when working with the game's pre-existing inventory design - specifically expanding it to give players more space.
Items are handled in groups of 35 - each page of the inventory and each slot in the armoury chest has that many items. It sounds like they can't all just be merged together after the fact.
On the "take away the second ring / offhand tool but still let people glamour it"... that doesn't work either. The glamour system functions by attaching glamours to specific items. If there isn't a gear piece in that slot, there is nothing to attach it to, and the glamour doesn't stick. You can see this in effect already if you're using the ARR-era gear that covers multiple gear slots, like the hooded cowls that stop you from equipping headgear, but only sit in the body slot. You can then apply a glamour plate that includes a hat, but the hat won't appear because there is no headgear in the slot to apply it to.