Lynne Cheney would probably do a better job than Sarah, but her last name would keep the “Bush’s and Cheney’s fault” mantra alive through the election.
Sarah could blame everything on Obama/Reid/Pelosi and focus the electorate.
The Bush/Cheney’s fault mantra will stay alive regardless of who the RNC Chair is. And Lynne Cheney can effectively assert blame to Obama/Reid/Pelosi even better than Palin.