The problem wasn't with O'Herlihy (it never is), it was his character. Prior to his coming on, the show was an entertaining adventure about a quartet of junior crimefighting computer experts that was every bit as much fun as Philip DeGuere's other then-current show "Simon & Simon" (Jeffrey and company even joined forces with A.J. Simon in one episode) - it was closer in tone to "WarGames" than "Scooby-Doo," which was fine with me even then; it also had some good writing to boot, such as one episode ending with their teacher informing the class that even though the FBI had commended them for their work that week, she was still going to punish the boys (the token female had done the homework) for not doing an assignment!
Unfortunately, when they were recruited to work for O'Herlihy's organisation (in secret of course), the thrill of their being freelancers was gone. It was the same mistake made when the Hardy Boys (Stevenson and Cassidy version) were taken on by the Justice Department - they went from playing outside the system to being part of it, and the show was never the same. But it was fun while it lasted...