For the people who don't see nothing wrong in Bethesda taking the mantle of Fallout, a good analogy would be imagining the makers of Call of Duty buying the rights to develop Red Orchestra 2. In both situations the company has made games in the similar genre while the style has been dramatically different. It's like waiting Uwe Boll to suddenly direct Oscar winning drama.
Bethesda wants to ensure that the content is suitable for teen audience so the drugs won't probably have side effects (they only empower), no alcoholism or narcotic related subjects (like addicted characters), no prostitution or sex (and I don't meant this as sex simulation but in a subject on post apocalyptic world), no strong language and well, I don't have high hopes for interesting characters, sub-plots or mature tones in the story either. Warrior of the wastes saves the world. After playing Oblivion, I just can't see them making anything except a dumbed down cross-platform teen action adventure game.
And I agree with Xendance that speculation isn't worth jack or poo. Ranting is just fun.