Beth is usually very good at taking feedback and working it into their designs. There were some large threads in Oblivion about being "rushed" along the main questline, always feeling like you shouldn't be exploring the world in your own way. There were huge discussions about this for Skyrim. When things garner that much attention, Beth seems to respond. Fallout 4 does not hurry you along except where it makes sense for individual missions here and there.
As for the dialogue going through major changes...
...this would be a wonderful consideration for future titles. There are two, simultaneous tightrope acts going on here, though:
1.) Bethesda is marketing for a mass audience. Incorporating deeper, more meaningful dialogue (which I am wholeheartedly for) would also mean that it may begin to reach over the heads of younger players. Middle school aged children make up a pretty huge chunk of Bethesda players. Sales could be quite drastically impacted if things get too mature in both content and execution for the dialogue to make sense to younger minds.
2.) The increased cost of production in the writing arena would significantly impact the overall budget of the title, meaning Beth would need to do all the business stuff to ensure that production still flowed with such a major focus shift. And think about how long it normally takes for a Bethesda title to go from inception to release.
If the next titles were to incorporate this, it would result in both a more complex and far shorter game.
If you add branches to a story, you need to add a different story for each branch. If there is to be another branch later on, you need to tie in the prior branch(es) and add an additional branch for each option at that junction, and so on. This exponential, tree-like growth of writing, and design, and recording gets HELLA complicated very quickly...and the player will only experience 1 possible path from beginning to end, despite the fact that ALL of that work was done for ALL of those other paths. Even if 470 hours of content, options, and junctures were added, it might only take 15 hours to move through a single path from beginning to end.
I think...this is exactly what they should do. I would pad the main quest with encouraged (or even required!) free-form exploration, lots of meaningful side-quests that really make you feel like you had an impact on the situation, and many possible endings. So if I finish the ENTIRE game in 4 or 5 sittings, I'm super excited -- I can now delve into again from a totally different angle with a totally different character and have a totally new experience with a totally different result.