Being an okay expansion sandwiched between two dumpster fires will have that effect on people.
During my time with legion, it was a decent expansion until I attempted to take it even remotely seriously. I ended up with aggramar’s and pre-buffed prydaz on my frost dk and found out it’d literally be easier to reroll off of my main since wrath rather than attempt to get a 3rd legendary. Also, the months of timegating in Suramar and then the Breaching the Tomb debacle killed any desire I had to play WoW until early this year.
I never got to see the “good” part of legion because the first half was so bad it drove me away.