Re: OT on the Whoniverse:
Yeah, it's a bit like Jack got the "why" of being a good guy, but not the "how." I like the character a lot, but he's really a charming thug with a power upgrade and good aim. He's the leader by seniority, not skill. Even the Torchwood organization seems to have realized this -- he was in a subordinate position until all his superiors got killed, despite being the most experienced guy around.
Torchwood's idea of "mature" was basically to add sex and swearing to nonsensical Buffy-lite. I think that happened a bit with the 7th Doctor novels after the old series was canceled too... unburdened by the demands of TV, they started working in sex, violence, drinking, and drugs, apparently just because they could get away with it.
I have to give props to Children of Earth, though; it was one of the most actually mature stories (in terms of social commentary and stuff) I've seen in a while. Jack was still a crap leader and pretty much everything bad that happened was all his fault, unless it was the Cabinet's fault, but the villainy was pure gold. Grimdark, yeah, but it worked.