His voice had started to become a problem about 10 years ago, in my view. He also started finding it harder and harder to keep all the threads of the discussion in his mind and to herd all the experts and steer them towards productive talk. The earlier episodes were almost all great.
listen to a 10+ year old episode and he sounds much clearer
as a native speaker its all fine and intelligeable, but for anyone ESL it'd be challenging bc its so much mumbling now