They made a conscious choice to change the show, because of the earlier time slot. I watched it when it debuted, but couldn’t roll with it. The great vibe was gone. Conan basically became the old Letterman show (although I didn’t watch his show either.) Basically, I quit watching those shows after Carson-Letterman left NBC.
I’m a Conan fan, but I’m wondering how much he’s going to change with the earlier timeslot. He basically replaced Letterman for me after the change.