I understand that it’s working as intended, that does not mean that it’s working well. I would absolutely prefer the vault to go away, but it’s here and it sucks.
How about they just reward an ilvl appropriate to the keystone you just completed. Come up with a scale and stick to it. If 15s are the top and that’s going to be 226, then just award it at the end. Don’t @me about raiding mythics, just put all that loot 10 or 15 or whatever ilvls higher than the highest M+ so they have their carrot and we have ours.