He's best when he has time to sit down and write it out. Stephen Merchant is very funny at one-liners.
But because he doesn't do it, it means hes arrogant?? I think if you suggest that you are ignorant and stupid. There are many number of reasons why he doesn't do them, one being that he doesn't need to do them, he has plenty of money.
Leevil - Jeremy Clarkson wrote about his time as presenter on HIGNFY that he thought it was going to be all staged etc. but that none of it was at all, and it was all off-the-cuff.
Fantasy Bazaar - I think you are living in a fantasy. No, he's not the only one who's written a great TV show. But he did write the most successful sitcom of the 21st Century, a follow-up sitcom that did extremely well, written three excellent selling books, as well as three sell-out stand up tours, starred in several films, written an episode of the Simpsons, and played a major part in the development of the podcast (thats not mentioning any of the awards he has won). So, even if he did feel superior and arrogant, he'd have reason to. But like I said, he has no need to go on the shows, as he is a household name already and his appearance would not help his status in any way.
Chris Rock never appears on panel shows. Neither does Will Ferrell. They must be too arrogant.