As a developer, the overview sidebar (duplicated in the overview tab at the bottom) is of little interest to me. I definitely don't like wasting what little screen space I have (only 2 27" monitors and a 24") on it. I understand that others might care about all that stuff so it probably shouldn't go away completely (although it is duplicative).
So I would suggest a setting somewhere in one's account profile or where ever you put user-level settings that would turn that panel on and off. At the very least control the auto-open functionality when loading or reloading a Feature page.