they could extend and improve the main story

I don’t think they can.

I have a strong suspicion that truly talented writers who are able to build memorable stories in great worlds are few and far between, and those that are willing to work in the games industry of today are as rare as hen’s teeth. Most companies, including Bethesda, simply don’t have the talent at hand to fix their mess, or there wouldn’t be a mess in the first place. The truth is probably somewhere between this, and the ol’ “eh, good enough”.