You keep saying this, but that's a straw man. From the moment it was revealed as a multiplayer-focused loot shooter, NOBODY was expecting a story on the same level as the Mass Effect series.
Personally I was just hoping for something that was a step above Destiny. I wasn't expecting lots of character development, relationships, or impactful choices. But I hoped BioWare would at least create an exciting, well-paced narrative that had me constantly wanting to know what would happen next.
I don't think that "not as bad as Destiny" is an unreasonable expectation for a BioWare game's story.