^ Daniel, Sam, Teal'c, Hammond, and Jonas were very much utilized as main characters, but were nevertheless 'support' for O'Neill, just as the other main characters on Las Vegas were 'support' for James Caan's Ed Deline.
I think you might be the only one that really feels that way.
While O'Niell was a big character, probably the biggest, there were growing more towards the other characters throughout the show. Plus Daniel was also very important. To me it was more a continuation of the movie, and as time went on we learned more of the supporting characters. Sam started having bigger roles on season two onwards.