I'm curious about this. In Fallout's dialogue, is there ever an instance when the PC might have a word or two that's automatically spoken to keep the flow of a conversation (like how? why? and?). One of the things about Bio's voiced PC's is that they have fairly long lines and multiple sentences. I'd like to know how FO4's dialogue compares in terms of sheer word count for the longest lines spoken.
I am sorry about late proper reply, but I've been without cable since the moment I started editing my reply. Back in action now and it feels like christmas 
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Good question. I do notice that you have the option to choose such questions now and then. Like more neutral showing interest kind of lines I imagine. Some of the answers can be amusing because the player choose something that that specific npc didn't quite like, or was strange ("weird" was a word used by one npc after I tried a somewhat humorous reply).
Perhaps this answers the question properly: After some hundred hours in FO4 have I only noticed disparity between the actual voice acting and subtitles/dialogue once, and it seems to be more of a grammatical difference than substance.
I feel that Bioware dialogues are richer, deeper and at the same time with more buildup somehow, but it might be because I like the Bioware characters/npcs far better. The "romance"/bff dialogues are probably more to the point in Fallout 4, but still sweet and strangely balanced, I think. Some NPCs got much text, not that it means I like them more.
Example of dialogues you won't find in FO4 is the dialogue tree you can start after visiting Solas the first time in Haven. It is, or got options to be, far richer, with more possible modifications on the relationship and I think also with far more varied outcomes, but that might be mostly coloured by my personality/impressions than actual substance/information.
Especially the female npcs/companions do I think have too little agency and because of that got less strength to them than a typical Bioware character got in the dialogue. Only one male character "suffers" from this in the same way as all the female characters, but doesn't make me sceptical to the writing in the same way and feels bit more organic.
In that FA4 mod has one of the arguments for making a listed dialogue that some lines can be bit long so it gets cluttered if having them centered in the form of a wheel. The mod also got a wheel variant though.
PS disclaimer: These are my impressions and opinions, not facts. We all have different tastes.