Legion did a much better job as disguising their flaws at the high end. M+ we’re faster and more fun. Legendarys made you feel powerful. Artifact weapons completed some classes and now have gaping holes in gameplay, etc
Legion had some of wows best gameplay in terms of class design and how fast/fun they play. So it’s easy to forgive its flaws when it does so much right.
Bfa on the other hand, takes none of the good with legion and just kept the worst of it.