I don't know that it's quite that bad. They had something with the revised Warhammer Quest - a ragtag band of protagonists with varied, interesting visuals, running around in a low-context dungeon scenario. AoS might've worked a lot better if it had been introduced this way, rather than plopped down as a single chunk of winding mythology and tongue-twister naming conventions. That Star Wars-y mix of low-context, limited POV worldbuilding with a lot of dangly bits left unexplored was something that got GW very far in the past. It's unfortunate that they can't seem to pull it off anymore, aside from dropping Mysterious Place Names every other sentence. That gets real old, real quick.
I think GW could improve AoS' background, but they'd need to take a deeper look at how they're telling their stories anymore. Right now, they seem to be responding directly to short-sighted concerns like "lack of civilization," which is really just treating the symptoms rather than the disease.