[Larry the Loafer]

The fact that they'd made the show so appealing to a mainstream audience was detrimental to the brand, in my opinion.

AIUI the original conception was to have a laid-back companion to The Late Show just before the viewers went to bed. I know little about Craig Kilbourn but I'm guessing he appealed to a more niche audience as opposed to the broad appeal of Letterman.

I don't think Craig Ferguson was "American" in his humour at all - it was his own brand. He was very much surreal and something of a loose cannon before he decided to relocate to the States. In his first couple of years, he went very much against the grain of your typical Late Night host; he was an open book, he was relatively unscripted, and the conduct of his interviews would eventually resemble something from an improv show rather than a mere plug for a film or show. There are a handful of short video essays on YouTube that draw attention to this, and this is how he gathered a very devoted cult audience. AFAIK the show received next to no publicity from CBS, and the fans either heard about the she via word of mouth or, like myself, found it by complete accident.

Compare that to Corden's tenure, where their social media game has been crucial to its success. Ferguson had no such game, so much so that it was down to very dedicated fans on YouTube keeping an archive of the show and its memory alive. Granted, Corden's TLLS seemed to go for the mainstream from Day 1; he appeared to have played straight from the same playbook as Jimmy Fallon complete with curtain, band, and countless forced games. It was the antithesis of the entire TLLS brand of relaxed and/or alternative late night entertainment. Any attempt to relaunch it with a new host will result in something almost identical to what we already have - it's worked, it's made money, and CBS will be reluctant to change that.

Some of us would've been quite happy with the simple pleasures of Daffy Dook...