Yeah im sure the legion will lament it if something like this where to be implemented. Still it would improve motivation to replay with a diff character since some content will be locked up with the choices u make. Its propably the one thing that i really miss in Bethesda games; my choices to feel like they matter. Most "choice" in any TES game or Fallout3 is actually more of a calculation than true choice.
There is a really good Extra Ceditz ep on the topic of choice - Click Me





