This would be an absolute gift to Trump. First, by pardoning her, Obama would be implicitly acknowledging she did something wrong. Then, Trump (and his AG) wouldn’t have to deal with her and could focus on the new Presidents agenda. She would be a pariah. The Nixon of our era.
Her new moniker would be Hillary Nixon.
And given she got fired from her legal job trying to make up phony evidence to frame Nixon.....
Nixon did get a pardon for far less. Many people around him went to prison. Presidence is send Bill, Huma, etc to prison.