The perfect example of a FNV quest were dialogue could change the course of a quest is the quest with the Super Mutants, and you need something I cannot remember what it was, but there are multiple ways of defeating this quest:
-You can do the approach of killing everyone and everything in sight
-You can speak with the ghoul and still kill all the mutants
-Kill the Ghoul
-Or complete the quest by completely speeching it out, talk to the Ghoul, talk to the Super Mutant leader, get what you need done, and everyone is happy
-I think there is also a way to just kill the Ghoul and take the Super Mutant side
But not only that there is this old lady asking for a ridiculous amount of caps
-You can barter her for a lower price
-I think you can even persuade her
-Or outright steal it
-Or kill her
The first quest that I did in F4, I was kind of expecting the same. It was the Kill All Raiders Quest in that Plant. I was half expecting the whole Fallout thing, where here I went to town on this Raider camp. I slaughtered the outside with my Sniper Rifle, I took my pipe rifle and went to town in sneak on all these Raiders, and expected when I walked into the room with Jared the raider leader, for him to come talk to me.
"You're the one whose been causing trouble in this plant"
"You've been harming a settlement"
"Harming, I don't know who you are, but you look like some pansy who doesn't know the hard times, maybe I can make you an offer you cannot refuse"
"Speak, but I am might not be interested, depends on what you're offering"
"I am offer [insert amount of caps] tell the settlement you killed us and I'll give you something nice from the treasures we found around here"
I don't know, but the point is that a game should offer replayability. That if I decline one option in the quest, I should want to be able to go back to the next playthrough and do the different options. I mean it's the problem I have with DAI, is that in the end every character with feel like the same character because the game lacks so different options. Yet, DAI, manages to add a bunch of different ways to complete their quest and some of them can be nonviolent.
I should be able to get the option of completing quest in multiple ways.