While a fifth season of Torchwood isn’t a sure thing, actor John Barrowman says that if the series comes back, he’d like to see the show explore Captain Jack Harkness’ background.
“I’m happy with what the writers write. I like the aspect of that particular job – I’m not a producer, I’m not a writer, I come in and I get the scripts and I do the job, and I bring the character to life and that kind of brings a bit of the pressure off!” says Barrowman. “But I think I’d love to see Jack time travel a little more, and I love going back in time to Jack’s past. I think that’s also nice to explore.”
Barrowman also explained that he enjoys playing Captain Jack because the Torchwood leader doesn’t fit the traditional mould of sci-fi heroes.
“He’s not a typical type of hero that you would see in a comic book or in a TV show, and that’s what I love about him,” he commented. “That’s what makes him fun to play. Also he’s a little bit naughty and he speaks his mind, and he’s got conviction with everything he does.”
Personally I think that Miracle Day showcased Gwen much better than Jack...he seemed somewhat off his game...yeah I know he was mortal but still his character didn't seem as strong as in the past. As for exploring his past...I would hope that would also include episodes of his (future) past...I know they delved into that a little before with Captain John Hart but I'd like to see more in that direction(his past...the earth's future) than in the earth's past.
I think Jack being off his game makes perfect sense. He's been immortal for so long, hoping to one day die. He gets much of his strength from knowing nothing can kill him. That's bound to give anyone a great deal of confidence. Now though, he is mortal again & realizes he can't jump into things head first & always make it out unscathed like in the past. Also, as he goes through the process of dealing with mortality, he realizes he doesn't want to die after all...although he's willing to sacrifice himself to save earth.