Was it because he was usually unintelligible in his speech? I think that, as a character, he has almost as much, if not as much, merit as Bill.
I think it's because he's kind of a gimmick character. That's not to say he's annoying or anything, but I'm certain people would get tired of lots of episodes about him because his speech pattern is something that you'd have to hear throughout the bulk of the episode.
Every character in KotH has their quirks, but his is such an integral part of what his character is that it might be a bit much.
>>93149001
He's also completely honest, fairly intelligent and no nonsense, which doesn't make for comedic opportunities
>>93148651
The episode where he gets spurned by that rich lady, and BILL of all people has to get him out of his funk, is kino.