I don't know how I missed this one earlier. According to UK Gameshows.com, CJ has announced that he will be leaving Eggheads. The quote on the site says that he wants to devote all his time to his acting career.
If its CJ's own decision, and he hasn't been 'pushed' - and I have no reason to suggest that he has - then good luck to him. Of all the Eggheads, CJ probably has more of the 'marmite' factor than any of the others - people either love him or hate him. They don't ignore him, though. The show has been going for a long time now, and he must take his fair share of credit for its success.
Good luck !