Once the Harrogate dust had settled, one thing that kept getting referenced over and over was the "Unique Voices" panel, and specifically John Connolly's comments on such. He's addressed what happened on his own blog and clarified some of the frustrations he feels with the crime genre - namely, that experimentation is limited at best and there's a "sneaking conservatism at work":
I suppose I feel that, as crime fiction has become more and more a part of the literary mainstream, its popularity has not been matched by a great deal of experimentation. There is, I think, a reluctance to take chances, whether that takes the form of fusing genres to create new hybrids, or experimenting with form or language, or anything that deviates from the rather traditional narrative structures that seem to be the norm in the genre.
I’m not sure who, if anyone, is to blame for this state of affairs, assuming anyone agrees with me. The writers, perhaps, for not pushing themselves? The readers, for favoring sometimes bland mainstream work over more experimental work at the margins, for wanting to be entertained instead of challenged? The publishers, for seeking variations on familiar themes, for favoring the series over the stand-alone, for, to put it simply, giving readers what they want?
There are, I think, a number of issues at work. One, of course, is market expectations, and that anything vaguely subversive, vaguely different from whatever "norm" happens to be in vogue is automatically going to be relegated to the margins because by definition, mass appeal simply isn't possible. That's not necessarily bad, because changing one thing is plenty difficult enough for most writers, and to do that well is usually enough to set his or her book apart from everyone else's.
But the flip side of experimentation is that in order to break rules, the writer has to be keenly aware of what those rules actually are - and by rules, I don't just mean narrative structure and form, I also mean pure storytelling that gets you in an emotionally honest way.