Giraffe, I agree with what you're saying about it all being pro-Cressida and the possibility of at least some of it coming from the Cressida camp. I do disagree, however, that it's being done in a way that makes her look good at his expense.
To me a lot of the stories seem to read more as either Harry's ready for marriage but she's not sure - which is just an expansion of the pre-Cressida line of Harry's ready for marriage but hasn't found the one, which has been pushed at least since William got married - or they're both talking marriage and Cressida has done so much to make him into a man who's ready to settle down - which can be seen as him escaping the image of being the Party Prince. I don't think either necessarily paints him in a negative light so much as it takes images of him that we had pre-Cressida and expands it. Even when the Harry's ready for marriage but Cressie isn't sure because of his reputation type stories are out there it isn't really anti-Harry so much as it's saying "the Party Prince is ready for marriage, but his 24 year old girlfriend isn't sure if he's/they're/she's really able to make that commitment yet."