It wouldn't have been a casuals focused disaster.
As much as I hate that it is so, the casual audience puts the hardcoe audience in the minority by a great degree. And in many cases, many who were once hardcoe gamers now find themselves on the casual side of things.
The greater the numbers, the more money there is to be made. And whether you or I like it or not, that is what Bethesda Game Studios is in business for: TO MAKE MONEY.
And Obsidian is not that great. I loved Neverwinter Nights 1. But I found Neverwinter Nights 2 to be somewhat "Meh!". I loved Knights of the Old Republic 1. But I found Knights of the Old Republic 2 to be somewhat "Meh!"
I find Skyrim's story to be satisfactory. It somehow manages to blend the notion of being a hero AND an average joe together. That lends itself to a deeper realism. Real life heroes are average joes when they do anything other than something that someone might call heroic. Take Oblivion for example. You play someone who ultimately becomes a Kingmaker, and when the main quest is done with you, you get nice armor that only an emperor would have worn, but aside from that, you might as well retire to your house and spend the rest of your life watching the mudcrabs breed. The game is essentially over, but you are free to wander about and just BE. Console players are consigned to that fate. But Bethesda in their wisdom has given us the means by which our stories, as heroic or average as we wish, may continue without end.
Obsidian's stories end.
Morrowind lives on today
Oblivion lives on today
Fallout 3 lives on today
And Skyrim will live on when FO4 or TESVI comes out.
In Obsidian's games, you pretty much have no choice but to play their stories their way. With Skyrim as designed by Bethesda, if I want to, I can say "Hang the story," and just go of and do whatever if I feel like it.
That's my opinion on the matter.