I don't understand why they wouldn't ask Bharara to continue staying on. The dude could potentially be a menace to the administration if a special prosecutor is ever needed.
I suggested elsewhere that this would free him up for exactly this role. Although I recall reading the law that empowered the appointment of special prosecutors was superseded in the late 1990s, meaning that Bharara (or anyone else) would have to serve as a Special Counsel rather than a Special Prosecutor.
Anyway, I would think it preferable for a formal inquiry into Russian interference in the election take the form of a Congressionally-mandated commission (
à la the 9/11 Commission) rather than any kind of prosecutorial arrangement, to deter perceptions of a witch-hunt. That way it could also be composed of distinguished elder statemen (and -women), as opposed to sitting members of Congress, as would be the case for a Joint Committee.