Do you agree that the players have prior knowledge of the rounds? Why would they have notebooks and keep jotting things down if it's all ad lib? Still difficult to talk for a minute without repetition etc. but it takes away a bit of your admiration for them.
i quite liked it, never having listened to it on the radio. I don't know what they jot down, but some of the contestants are worth their weight. Sue Perkins is a lively player, Paul Merton clever, and Nicholas Parsons a wonderful mediator.
They are allowed to repeat the words in the subject so it may just be a case of jotting down the subject so that they are sure about the words and what can be challenged.