That is absolutely false.
Azerite and neckle is far superior to artifacts. Simply because it's not overcomplicated crap that you will miss next expansion, artifact done right.
Both campaigns were mediocre.
Generic ship is far superior than class halls, doesn't force people to have alts, doesnt generate insane amount of gold out of thin air.
Story was mediocre as usual, legion wasn't better than BfA.
BfA class design is far superior than legion because:
1. Not dependent on one item to function
2. Working out of the box
3. Consolidated, balanced and fun
There
BfA is better in every aspect than legion except for corruption.