Those of you who read my chapter on iheartpresents will know it begins with my heroine, Libby in the hero's rubbish bin. She's there (literally) digging up dirt on the hero who she needs to write a biography about.
The editors thought this was a rather desperate way to behave and made Libby appear a tad unlikeable. They believed the external conflict made her appear unsympathetic to readers as she didn't behave like a professional young woman and went on to do terribly devious things in an aim to find the truth out about Matt. She goes behinds his back to get information during the novel and although she doesn't end up using this material, she's still decieved him. The editors believed her obsession to write a good article overruled her love for the hero and in a romance, this is of course, a no-no!
Basically there are things in Libby's character that make her unworthy of a Modern Heat hero and therefore she and the story didn't make the grade.
I guess what I've learnt from this little part of the rejection is that our heroine's really do need to be outstandingly special. They may have a little self doubt, they may have had bad luck in the past, but they need to be morally upstanding and likeable!!