It seems to me that while previous characters had pasts, these were largely passive or independent from the player. Fallout 4 seems to have assumed some choices for the character already as if they had taken the initiative, which is a tad problematic depending on who you want your character to be.

E.g.

Fallout 1 - You live in a vault and someone sends you out to fix the broken water chip. Everybody needs water to survive, so while it's a backstory, it's something important that anyone from any background can get behind.

Fallout 2 - You're a member of a tribe and someone sends you to solve the famine. That's a pretty good start out, as nobody enjoys a famine. Same as above.

Fallout 3 - You live in a vault (of which you have control of the player during stages of his/her life), until your Dad leaves. Everyone alive has/had a father, and the intro is set so that you can either be a dick to your Dad ("You left me to die there!") or catch up and reconnect ("I understand because you want to help the Wasteland have water"), and his death soon after you catch up is hardly an influence on your story for your character. The main quest is a bit of a stretch depending on how you want to play your character, but that's another matter.

Fallout NV: You're a courier who is delivering a package, only to get hijacked and shot in the head. From here you can take the story as a loyal package delivery boy/girl and reclaim the package, or as revenge and kill your assailant... or get caught up in everything else because you hated the job and there's a problem in Goodsprings that looks like a good distraction. From the get-go you have very little backstory, hell, even why you took the job is left up to you (Was I your average NCR citizen, a Vegas-born independent, a sufferer of amnesia brought on by the injury, or a retired raider intending to enjoy retirement with some honestly earned caps?).

Fallout 4 - You're a Pre-War army vet./lawyer who has a son, until the war begins and you're SO is killed and your son stolen... woah woah woah slow down there... It's already set up some major backstory elements, such as your job (a pre-war vet is going to have some pre-war knowledge, combat training, etc, while a lawyer would have... speech skills, charisma?), your sexual orientation (if I'm straight from the get-go, why would a nuclear holocaust and 200 years in a freezer turn me gay/lesbian/bisexual?), even your choice to have children is taken from you (may not sound like much, but if the whole story revolves around something which you've decided your character either doesn't care about or would never do in the first place, the whole thing is moot), as well as where you'd decide to create a settlement for yourself (If I lived there 200 years ago and had a knowledge of the area before the bombs, why would I choose to live anywhere else but Sanctuary?)

Being Pre-war also creates another problem. While Boston is big, wouldn't I know some notable pre-war locations, and even some of the skeletons/ghouls littered around the area, would that change my stance on how to treat ferals (much like the group that sheltered in Kiddie Kingdom at Nuka World; treating ferals as "an affliction" that could be treated because I might have once knew them.

All of these are some serious hoops to jump through and require some good mental gymnastics or a complete abandonment of a character because the background has already been set-out for me. This comes before I've even gotten on to the voiced character, which can shatter the already shaky illusion I wanted to create for a certain character. If I wanted to create a Black-Gay-Irish raider-type character just for the sake of it, the backstory and the voice throw all these out the window, and so my hands are tied to somehow explain it all down to PTSD and that I suffered a stroke that changed my voice.

Don't get me wrong here, the voice actors were good (especially making one of the sarcastic options literal), but unfortunately it clashes with how I want to play my character, and future characters in the long run.

Pre-made, voiced characters (or characters with far too much backstory created for them) have little place in a game that intends to be other than the main story, an open sandbox of possibilities. The only solution would be a selection of voices, an increase in the number of lines from every one, or a silent protagonist and a selection of text options, the former being VERY expensive.