Sure.
Covenants failed because the main reason you had them (abilities) made players forced to pick them or else you were crippling your class in terms of damage/utility/healing/etc. This would be an easy solution if you could change covenants with ease, however - originally, there was a downside of changing covenants that locked you out unless you did some arbitrary grind; this making the system hard to swap. On top of this, renown did not carry over between covenants making so you had to grind out renown to even catch back up to other covenants (Making it harder to covenant swap without time put into it).
Maw simply sucked because it was a non-mountable zone that punished exploration with the Eye of the Jailer mechanic.
Torghast (and Legendaries) failed because it was the only way to get legendaries, making the content mandatory without much other reason to do it until Blizzard added the RNG chance to get a cosmetic piece in the shop at high levels (which wasnt until 9.1). Outside Twisting Corridors, there was very little option reason to do Torghast until Blizzard implemented optional cosmetics for players to do. On top of this, the Legendary system also required a crafted piece that was price gouged out like crazy.
Note: a lot of these things were fixed in later patches, but the initial damage they did on release combined with a Blizzard slow to repair - didnt really win favors for a lot of players.