Discussed: "Charlie is you guys' best friend? I really didn't know he was that close."
"Who is this Charlie guy? Was he in the book?" "Yeah, but he was not that big of a character?"
Played For Laughs: Charlie was somewhat of a Cloud Cuckoolander in the original show. In the adaptation, he is even more of one due to Flanderization. This, combined with his increased screen time, makes for a much more humorous adaptation.
Played For Drama: Charlie dies in the final episode of the adaptation. Because he's a major character, his death is more dramatic than it would have been in the original.