It is true what you say - I don't think Moore makes it through the season without getting banged up and missing some time. He's just prone to taking some big hits every now and then like in the Steelers game. That doesn't mean we need to sign a guy whose media attention is going to create a QB controversy from the moment they get here, which is especially silly considering Moore is the first Dolphin QB to win a playoff clinching game since Chad Pennington despite ample opportunity for guys like Henne and Tannehill to step up in December.
Teams haven't signed Kaepernick because his play on the field isn't good but his ability to disrupt and organization, whether you think its fair or not, is high. Teams don't sign backup QBs with a lot of baggage, they sign a guy who isn't gonna cause an issue, is gonna help the starter and the staff prepare for games, and can hopefully play in a pinch. If you have nobody and nothing else to lose, signing a guy like Kaep to come in and start might make sense. But we don't have nobody, we have a veteran QB who who has a better record as starter than a lot of QB's around the league who has played well given his chances and seems to be well liked by his teammates and brings a scrappy energy to his team. It's not ideal for him to start for an entire season, but in the absence of another legitimate starter you need to bring in a guy who can be Moore's backup and hopefully contribute when needed, not a guy who will turn the season into a crapstorm.