It's as the title suggests.
Let's say we never gave up our Artifact Weapons, that we had to start from scratch but still kept them and they added new mechanics and pre-existing traits borrowed from the Azerite Armor/Essences/Corruption Gear/Shadowland Conduits... Treating Artifact Weapons/Artifact Weapon Trees as a temporary Evergreen system up until Dragonflight's launch and talent trees.
It is still borrowed power, but it was a soft reset where some traits were changed to make the playstyles a bit more interesting and adding new abilities. Essentially turning the Artifact Weapon Trees from just another expansion exclusive system into a secondary talent system.
Would Artifact Weapons have improved expansions and gameplay if they kept them going in BfA and Shadowlands? Or should Artifact Weapons just stay as a memory of Legion?
Edit: To make this a little more clearer to understand. I'm not suggesting that we stacked Artifact Weapons, Azerite Armor/Heart of Azeroth, and Covenant Powers/Conduits on top of each other.
I'm asking if Artifact Weapons REPLACED Azerite Armor/Heart of Azeroth AND Covenant Powers/Conduits... From the beginning of Legion to the end of Shadowlands, we just relied on our Artifact Weapons. No other systems, just Artifact Weapons. Would it improve the gameplay for both expansions (BfA and SL) or should Artifact Weapons stay as a feature only in Legion?