I agree with the further idea cited of having a non mentoring judge, as judges will always vote for their own acts. It needs mystery and tension. Or why not have completely a separate group of mentors, and judges, so there is no conflict between the roles? Spicy!

Isn't that what the Voice UK does?

It sounds good in theory, but the producers will be still pulling the strings no matter if the judges are mentors or not. So would it even improve the credibility of the show.

Do you really think an 'impartial' judge would be impartial? They'd be told what to do too in my opinion