Same here, KMR. But the perception from DC, the publicity unit, the network heads etc. was that it was the vampire thing that made it so huge.
Exactly the same thing here, too. I know there are many fans who do, but I've never watched DS just for Barnabas. I enjoy all the characters. And some may find this sacrilegious, but at points in various storylines I find the other characters a lot more interesting than whatever Barnabas might be doing. When he's missing from the storyline, more often than not I don't even notice. Back when DS was on Sci-fi people would make comments about how they'd been missing Barnabas because he hadn't been in the last several episodes and I wouldn't have noticed until they'd pointed that out.
(I am not sure if the "coffin set" includes all the interviews)
Back when that set was being publicized they promised that all the interviews that had appeared on the previous DVD/VHS releases would be included in the set. I seem to remember that they even said that some new interviews would be added. However, I've never checked for that. There are discs in the set where more than one video is featured at the end of certain discs, but it may have been that same way on the original discs as well.
Somewhere there's a list of all the extras on the original DVD releases. And all the extras for the "coffin set" are listed in the booklet that comes with it. But I've never compared them...