I certainly don't want her head on a plate. I think it was a daft thing to say, but it can't be easy hosting a live show. The reason I think she should stand down from QT is because it is not the first time she has been very partial (the Mick Lynch episode was particularly egregious, so sticks in my mind, but there have been others) and before she made the comment about Johnson I was already rolling my eyes at her chairing a debate about Lineker's comments on Twitter when she has used the BBC to push her own views.
FB is personable and pleasant, and should, IMO, continue to host things like the Antiques Roadshow. A more controlled presenter should take over QT (it's time for a change anyway), and I would suggest Emily Maitlis, who I think is a miss to the BBC.