No to the main, numbered chapters.
TES is non-linear. TES has a main story, but it is never the only attraction.
New Vegas was a linear game cleverly disguised in a non-linear box. The side quests were almost exclusively dealing with the Main Quest in some way or another. That isn't TES. Bethesda is TES.
That said, I certainly wouldn't mind seeing Bethesda give Obsidian the Adventure or Legend franchise to give another shot. Another Redguard or Battlespire, perhaps?
That's generally my feeling, although I'd rather a new spinoff than a return to a previous one.
I imagine not screwing up the lore would be among the hardest things, given how much of it there is now. And the way Todd also talks about balancing the humor and keeping it true to the tone of the game - details like that I can't imagine another studio doing as well. Still, the wait between TES games can feel painfully long, so I might be willing to take the chance with a spinoff title.
In any case, while Todd doesn't rule it out, it's clearly not too likely to happen any time soon.