But what Order Hall/Artifact specific content did Legion truly offer beyond endgame questing? BfA had the same amount, if not more content than Legion at max level in that regard with the Faction War questline.
Seems to me like a false comparision, because while yes the game would have been lesser if we took out that content and didnt replace it with anything the game has clearly shown itself to have that content as a baseline, just with a different coat of paint each expansion. In Legion it was the Order Halls, in BfA it was the Faction War, and in SL it was the Covenant campaigns.