I think in Gwen's case it was the unrelenting meta from the PTB that kept saying she was something other than what was on the screen that finally moved her from the meh to the grr column. I know I write Jack as vulnerable, but that's because I see a lot of defensive mechanisms in his behavior. It's also why I see Ianto as a protector. It's on the screen. What he did for Lisa, and all the little things he does for Jack.