When Peace Talks finally broke, I read it and was immediately disappointed. Battle Ground came out, and I loved it.
My problem with these two books is that neither one felt complete. BG felt rushed, PT felt slow. Neither felt right.
Jim said he wound up writing "four-thirds of one book" on his first draft of PT, and wrote the last third of PT and BG to produce two. It didn't feel like that to me. Scenes like Murphy's death, which were emotional for me, just didn't have the kind of impact I felt like they should have.
To me, it felt like Jim wrote one book, then added some things and cut it somewhere in the middle to turn it into two.
I liked the story, I liked the individual scenes, and BG was one hell of a ride, but there's a disjointed sensation to the whole situation that just felt off.

Here are some I think about more often than I should:
1. The identity of the Demonreach prisoner.
2. Additional Starborn reveals, including other Starborn, and more information about their purpose, powers, and functions.
3. Possibly related to that, Elaine reveals of varying drama.
4. Time travel shenanigans (Hounds of Tindalos, which appear in Peace Talks, were conceptualized as entities who only begin to "notice" their prey after they've traveled in time; I think it's obvious that Justine sent them, considering where they were when they first attacked, but I don't think it's an accident).
5. I still don't know why Thomas went after Etri in Peace Talks, and he only tried to warn Harry about Justine's Infection. Did she threaten their baby? What was Thomas trying to accomplish? Was/is Etri Infected? Was Thomas? How is Thomas's assassination attempt (assuming it was genuine) related to the Justine reveal?
6. Chandler's fate. I think it'll be... unexpected, whatever happens (for example, Chandler being the Prisoner is frequently tossed around on here). I think it'll be something we've never thought about.
7. Hastings. I've got a ton of theories about what went down during Hastings/the Battle of Stamford Bridge, the Norman Invasion, and the Outer Gates. I think I'm probably going to be wrong about a big chunk of them, but they've brought up Hastings too often for it to never be revealed.
8. Some thought that Marcone would bear Amoracchius during the BAT. I think that's out of the cards after BG. Who, then, will carry the Sword of Love? Will that be Thomas's triumphant return? Murphy's? ...Maggie's?
9. Assuming Justine did not fake her pregnancy, I think we're in for some reveals about the nature of their child. What effect is there on gestation and growth if the mother is Infected the whole time? What happens when a White Court Vampire has a child with an Infected Mortal? I don't think there can be no effect.
10. Margaret LeFay's necklace. I've been saying it since Changes: that stone isn't just magic MapQuest (is that still around?) that tells you the fastest available route. It operates like a diary; it would not surprise me in the least to learn that there are at least some additional entries in it.
11. The Proven Guilty mysteries. Still no real answers, and I'm praying they surprise me.
There are, in all honesty, too many to count. Most books have at least one good reveal (at least for me).

There is an enormous difference between not using a condom and going after the people who kidnapped your daughter. They're not even remotely comparable.

Disagree with your interpretations.  I agree that Harry was irrational all through Changes, but it was because he cares, not because he's got some noble death fixation.  Think:  Harry has been an orphan since he was what, 6?  His adoptive father was abusive, twisted, and evil, and then was killed by Harry when he tried to mind control him (and succeeded in mind controlling Harry's first gf).  His first job as a private detective was with a guy who searches for missing children he rarely finds and apparently can only afford to live in his office in a run down, bad part of town on the border of gang territory.  With Harry's skills, he could easily have built a much easier life for himself, but he doesn't, he continues to do what he thinks is right.  He is constantly describing how happy Michael's kids are in the books.  Also, remember when he got his hand fried?  Harry has a fixation on Family, and another on saving and protecting children from all the horrors of the world.  He's going on , trucking along, witnessing all the horrors of the world (not least of which is what the Red Court does, especially when it targets young people) and burning them down whenever possible for people he has never even met before, and then, suddenly, he finds out out of nowhere that not only does he have a daughter, but the red court has her and are probably planning to do something horrible to her.  Changes is nothing but Harry dialing up his usual behavior to save his own daughter, his family, you know, that thing he always, always wished he had for his whole life.  The situation has changed, he now has something personal to fight for, and he goes completely off the rails trying to do it.  Make no mistake, children of your own change everything, whether you've met them before or not.  The only people who wouldn't be affected are those who are married to cold, hard, logic (or people trying to apply cold economics to Harry Dresden), and when has that ever described Harry Dresden?

I agree. All of Changes is perfectly in line with the way Harry would act. He's predisposed to go nuclear when women or children are involved. This happens to be not just a little girl, but his own. Naturally he's going to go full Liam Neeson. I don't think it matters much whether or not Harry's met her; he was always going to lose his mind and unload as much as possible in the direction of her captors. I just don't think many of us expected it to be at this scale in the end.

On another topic: I never cared for Susan. I didn't like her in the first three books, didn't like her when she became "She-Hulk" by Death Masks, and certainly didn't like her when we found out that she was hiding Dresden's daughter from him. I mostly found her annoying. In my opinion, her best contribution to the series was giving Harry his duster.

Mostly the whole thing is stories we've heard a hundred times. (If I'm going to go to the effort of seeing someone in person, I'm going to have looked them up on Youtube and not ask a question that's been asked a hundred times).

Typical. Let me guess:
"Did you plan out the series from the start?"
"Did you know that Harry was going to become the Winter Knight?"
"Wow! Molly's the Winter Lady! Did you know that was going to happen?"

I think at another fan interaction, someone claimed Jim had titled it Body Slam.

Well, agree to disagree. I think Jim would've written the fifty words handwaving the reason he couldn't use LC in Turn Coat rather than excluding it altogether if it wasn't meant to be a hint at something.