I would say that either Jack's not going to be in Torchwood (John has gotten a part (probably small) on Desperate Housewives, so it's not like he NEEDS Torchwood) or if he is on the show he'll show up just long enough to make the hard decisions so Gwen doesn't have to. RTD has said that 'The fact that [Gwen] has survived -- and that she hasn't become walking wounded -- really is a story in itself.' I can't see Gwen being the leader of Torchwood and not becoming the walking wounded.