Republibot 3.0
Regular
He's 57 according to the interwebs. That's hardly old – if Sly Stallone and Arnie and Harrison Ford and Bruce Willis can still be action stars in their late 50s and 60s, I'm sure Biehn could do Gideon. And why couldn't he be that old? If we're rebooting why not make the captain a little older?
Arnie hasn't done any action in an action movie in like a decade. Sly specializes in men of action who are in their autumn years (Rocky Balboa, Rambo, his current boxing comedy, etc) They're more dramas about mortality than straight-ahead actioners. Bruce looks like an extremely buff Don Rickles more and more as he ages. Harrison Ford is looking long in the tooth.
Also: these people are in unusually good shape for their ages, owing to extensive personal training and diet every day. They take months to get in shape for their movies, and training, and they don't do their own stunts. And a movie has a budget to make things look better than a TV show. It's an entirely different animal than the grind of a weekly TV show.
Patrick Stewart was about 45 when TNG started, and in very good shape for a little guy of his age, but he wasn't an action/romantic lead. He was simply too old to be credible. How many fistfights did he get in in 135 episodes? Like maybe five?
Richard Dean Anderson was a very serviceable older lead in SG1, but part of that was that they addressed his age quite a bit. He was continually complaining about his knees and stuff. And he wasn't a romantic lead. He was kind of an anti-romantic lead through much of the show. And even then, after 5 years, he started taking a backseat in the show because he wanted to spend more time with his family, and also he really was just getting too old to do rigorous shoots every week.