I've seen some people give Ricky Gervais shit on this site for not being as funny as Karl Pilkington, which has a thread of truth to it. They also say that Stephen Merchant is useless and that the beating heart of the radioshow/podcast/tvshow is Karl, which also has a thread of truth to it. I feel like the main reason the show is as good as it is, is because of the dynamic between the three of them. In this case, the sum is greater than the total of the parts. If you took any single voice out of the show, it would be worse. It's possible you could find a better replacement for either Steve or Ricky, but I wouldn't put money on it.