There has been a trend of the Dresden Files novels getting longer, though Skin Game had a lower word count than Cold Days. Also, if you compare the Cinder Spires book with the first book of the Alera series; well, there is no comparison. "The Aeronaut's Windless" a much longer and more involved story. Now we know Jim has had various life issues which have contributed to Peace Talks taking so long to get done, but does anyone else think (because I do) that Peace Talks is going to be a more complex story (or have more stories to tell within it) than what we usually get from a Dresden Files novel? I mean Skin Game had a pretty basic story idea; a heist story where Harry was forced to work with Nicodemus and both of them would try to double-cross one another. There were of course unexpected complications, but I'm just talking about the main plot of the novel. Many of the early novels had easily identifiable A and a B plots. For example, in "Blood Rites" Harry is trying to stop an unknown foe who is using an entropy curse to kill people on a porn movie set and at the same time he's organizing a strike team to find and kill Mavra. These A and B plots are often related to each other in ways that Harry didn't understand, but again, I'm just talking about the basic plot structure, not how various elements might be blended into the overall story arc.
I'm thinking that in Peace Talks, Jim has more balls to juggle than in perhaps any other Dresden Files book before it. If you've read the preview first chapter you know that
Thomas told Harry that Justine is pregnant and Warden Ramirez told Harry about the upcoming talks with the Fomor and asked him to be part of the security team guarding the talks.
So if you didn't read the spoiler there are two issues that Harry will be involved with in some manner. However, that leaves many other potential complications that in themselves may become their own, let's call them C and D plots. Not to mention that the first issue in the spoiler is a rather open-ended one. It's not a straightforward idea like, I want you work with Nicodemus and “I expect you to skin them alive” or "They've taken our daughter." We can only guess where this story element may go and there is really nothing in the earlier novels that might give us more than a tiny hint of how this could play out.
Jim has said that Changes, Ghost Story and Cold Days could be described as an internal trilogy within the series, that turns it in a new direction. I would argue that Skin Game should be added to this list and call it a quadrilogy within the overall story arc, because SG settles the issue of the "parasite" inside Harry's head we learned about in Ghost Story and it demonstrated that Harry; though at times with some difficulty, was learning to control the Winter Knight's mantel. So we had Harry's life deconstructed in Changes and it has taken until the end of Skin Game to see that a new life is now possible for him. So now that Jim has fully turned the ship around that means Harry will face more complicated situations to untangle and I think they begin in Peace Talks.
Just to give one example, we don't know what the future holds for the White Council and its most prominent members. In Changes it almost seemed like a civil war was possible or that a coup was about to take place. I suspect Jim was setting up serious complications and likely endings for one or more characters on the Council. I won't be surprised if we see one or more of those complications or endings happen in Peace Talks. That is just one possible avenue Jim might explore. Think about all the other possible complications that might arise, and even if only one or two come to a boil, you've got a bigger and hopefully engaging novel for us to (eventually) read, and one that takes some effort to tie together. All that said, I'm hoping that really soon we will read that Jim has finished or as he has often done in the past, he announces that only the denouement is left to write.
PS: If you would like to make a guess at likely complications or plot twists we might encounter, feel free to do so. I think it's about time we start compiling a prediction list and later see who came closest to the mark.