If they wanted it to be more natural, then why didn't it occur at all in Val Royeaux? Honestly it was the one place where you could safely stand around and not get attacked while waiting for dialogue and yet it was the one place it never occurred.
From what people have indicated concerning dialogue, it would seem there were some places where it seemed to trigger more frequently than others. If this wasn't intention by the Devs then clearly it was some sort of bug. They said that if you want to encourage dialogue, do something simple like picking elf root. Is that why we needed so much in the game, because of the link with encouraging your companions to speak? The problem was this just didn't work. I walked round and round in circles in some places, just looking for elf root and other herbs, then stopped to admire the scenery, just waiting for someone to say something, but silence. Then finally got fed up and started to walk towards my next destination, was spied by an enemy and just after, guess what, my companions start talking.
If the timer was 15 minutes that was just too long. It should have been combat finishes, then 5 minutes until next dialogue, because that would be nicely filled with sorting through loot, picking some more elf root, before moving on. I just didn't want to spend 15 minutes avoiding all confrontation or moving anywhere significant. Did the 15 minutes include reading codices?
You say that your humor doesn't often come across in your posts, so I can't tell if you're serious about the whole elfroot thing. They don't mean that elfroot itself has a specific impact on banter, it's just something to do while you're wandering around.
I agree on Val Royeaux, but that still doesn't take away from the idea of wanting it to be natural on ALL of the other semi-open maps in the game. Hinterlands is really huge and open, and the player can wander all over the place. If trigger points were the only means of triggering banter, many players would miss it because of the structure of the maps, which is why my suggestion would have been to have one or two triggers in addition to the standard DAI method.
I do agree on the timer though, and I'm someone who explores every inch of all of the maps just to fill them out.
To your question: the timer only goes while you are exploring. It is reset if you enter into a cinematic, change maps, or see the loading screen (going into the Redcliffe tavern or chantry). Looking at menus, or codex, is the same as putting the game on pause, the timer is paused as well. Fast travel within a map has no impact. The only thing I'm not sure of is whether the non-cinematic conversations with NPCs has an impact, such as talking to Horse Master Dennet and so on.