The Governor General does, and must, have real power. The King-Bing affair was controversial, but the Governor General's action was arguably justified, and negative opinions of it do not set a precedent that the Governor General can never do anything. The Governor general arguably should have taken a more active role in some recent times - when Paul Martin and Stephen Harper were trying to dodge (successfully, it turned out) votes of non-confidence, which have to be allowed in a democracy. Certainly, if the Prime Minister blatantly violates constitutional convention, such as by refusing to resign after losing the confidence of the House, it is necessary for the Governor General to dismiss them.
Since the Governor General must have real power, it follows that the Monarch must have real power regarding the appointment of the Governor General - rejecting the Prime Minister's request to dismiss or appoint a Governor General when this is clearly an attempt to fill the position with someone who will allow the Prime Minister to act non-democratically.
A dead person will not be able to fulfill this role.