Well, the thing about the bit bolded is that you don't really know.
Now, I know forward planning on how to implement huge decisions isn't necessarily seen a a requirement in the UK now, but you would like to think there would be some sort of plan for what replaces it.
The only real advantage of monarchy is that it largely takes away any political element to it. I'd like to think we'd go for some form of nominally non-political symbolic/figurehead head of state instead, but there's a real risk it turns into another political position with an the friction that brings.