I guess its good to find out what happened to the other characters but the scene with Carrie saying I do to Charles and then seeing the lightening streak seemed so final. it was a perfect end
im not your buddy guy, im not your GUY buddy, im not your buddy guy
According to the audio commentary on the DVD/BD, that is the original ending.
Though, the result of some test screenings, showed that the audience felt cheated as to what happened to the other people.
After all, it is a film about friends almost as much as about Charles and Carrie.
So, they scrambled a photographer and shot the added wedding photos guerrilla style (i.e. without a permit), after the filming had been done.
RIP Ian Richardson (1934-2007) http://akas.imdb.com/name/nm0007183