No, we really can. Legion or no, WoD was the expansion of time travelling Orcs, Garrisons, class pruning, no flying, Blizzard nuking reputations & placing traditional reputation reward mounts on the Cash Shop, etc. The expansion was conceptually bad. You can’t build a GOOD EXPANSION on a BAD FOUNDATION.
Not really. This is why I brought up MoP. Despite my gripes with some of MoP’s features, it wasn’t a “bad” expansion. It did have a considerable content drought at the end, which was comparable to WoD’s. WoD was atrocious and lacked content, so clearly “Subsequent expansions cannibalizing current expansions” isn’t the entire story.
We could go bit by bit over various expansions and point out what was cut & why Blizzard stated it was cut, but I don’t think that’s necessarily. The MoP drought is more than sufficient to pop the “Legion ruined WoD” idea.