This is an interesting discussion. I'm prepping the first chapter of Mummy's Mask right now, and I've actually added a warning to my players that there are surprisingly frequent opportunities for interaction in that adventure. ("Surprising," because the initial concept sounds like a lot of dungeon delving, and so they might not think they need to build characters that are equipped for social scenes.)
Then again, my group likes to stop and talk to almost everything. When I ran Fortress of the Stone Giants, they did most of the exterior and ground-level without a single fight, by intercepting and recruiting a bunch of different factions. (They did gain an entire character level during that time. Okay, they did about half a level-worth, and then the running joke took over. "Let's see if we can get to next level without rolling initiative," someone challenged. And I ran with it, building on the info in the adventure. It was awesome!)
I think many of the adventure paths really do make this possible, if you can get yourself to set aside the monster stat blocks and allow other options when the opportunity arises. And yes, if you can ignore the "fights to the death" statement that is so common in Morale entries. Admittedly, if you spend a lot of time updating stat blocks and working on the combat-prep, this can be really hard to do.
Oddly, I think that "fights to the death" is made necessary by the long stat blocks and strict limits to word count. If something doesn't fight to the death, then you need at least a couple of paragraphs explaining what it wants and how it should interact. And you might need info on what happens later if that creature survives the adventure. If something "fights to the death," that's all the author needs to say. And that doesn't mean I am required to have the creature fight to the death - it just tells me the adventure assumes the creature is unlikely to survive, so if they happen to survive anyway, it's up to me to figure out what to do with them, but I don't have to worry that the next chapter will have further info about them and contradict whatever I came up with.