They could have just recast Mike Seaver with Scott Weinger

When Kirk got older and started having moral objections to the show's scripts, it would have been easier for to him to simply resign the show and for the producers to get Scott Weinger (DJ's boyfriend Steve from Full House) to replace him. Although they don't resemble each other now, Kirk and Scott looked and sounded enough alike to make the transition (not to mention the characters they played were similar - Steve was a total idiot on Full House, much like Mike Seaver). Of course, I'm not saying I have a problem with Kirk's objections. I appreciate clean entertainment and if Kirk's staying on the show helped the writers avoid putting bad scenes in the episodes, then I think it was probably for the better that Kirk stayed.