In an unvoiced RPG you have no choice about what your protagonist will say, the lines are up there on the screen, so that is what they are 'saying'.
This is identical to a voiced protagonist where you have no less choice about the words, still none.
The only difference is that a voiced protagonist will not list the full text, else you will read the text, then hear the text:
'You piece of scum, I'm going to blow your brains out!...'
'You piece of scum, I'm going to blow your brains out!...'
That would get irritating in about 30 seconds.
Bethesda have been at pains to point out the extensive recorded dialogue.
This does not prove but implies that FO4 will achieve or come close to the mixture of choices that a non-voiced protagonist achieves.
Sure, you can head canon tone with text so you could say:
(with a jokey sarcastic tone) 'You piece of scum, I'm going to blow your brains out!...'
Though they may still open fire on you despite your 'reading' of the line.
That leaves the last potential issue that a 'short text' could mislead you about where the 'line' will take you.
but that's a small price to pay for higher levels of emotional engagement.
Sure, there will be some criticism, but that's just down to the passing of a gaming mechanic
that for reasons of fashion and technology is transitioning.
In short:
Don't worry about it, it will be fine.
(and politely, it ain't changing...)