Everything we've seen so far suggests that the game will offer less than or as little meaningful choice as F3.
Voiced protagonist, essential/immortal NPCs, binary factions, and an on-rails narrative.
It is amazing that Bethesda can spend so much time hyping the open world, the crafting, and the shack building, whilst apparently setting the thing up to have very little agency for the player.
There will apparently be (further) simplified character development - the rp system is being further stripped back = less opportunity to customise your character. (Even though there may be more appearance options.)
The use of essential NPCs will almost certainly be reflected by their use as narrative drivers and probably to hang plot twists upon. (Which will be less surprising because of that - Dogmeat gets his guts shot out and turns out to be a Synthetic? But that might mean..?! Something like that.)
The use of a fully-voiced protagonist will certainly dilute the ability of the player to intelligently influence dialogue outcomes, simply because you're choosing a theme rather than specific dialogue.
I like Mass Effect, but ME3 is an interactive choose-your-own-adventure-gamebook. I like it, but I don't want that from a Fallout game. I want more ability to craft my own experience.