Diamond City is great. Fenway Park is now a shantytown, Green Monster and all.
Alas, it's one of the few truly great things in this game. I don't think I've properly stressed how dumb the story is. F3 was about a son trying to find and reconnect with his wayward father, and F4 is about a father trying to find and reconnect with his wayward son. Yes, Bethesda, you managed to thematically connect the stories of these two games, but why? How exactly does knowing that this story is kinda-sorta reversing the family roles in F3 make it a better or more fulfilling story? And yes, it's "father" specifically, not just "parent," because just as Bethesda means for you to play the game as a generic good guy, they also mean for you to play it as the father, not the mother. It turns out I was mistaken above when I described the PC as a veteran in gender-neutral terms. The father is the veteran regardless of whom you play as, and so he's the one who gets a vaguely-heroic backstory as well as the voice-over in the introduction, while the mother is basically just a housewife. This is his story, not hers. I'm not bringing this up as a feminist criticism of the game (although if I were, I'd call attention to the fact that the mother is literally fridged in the introduction), but as a sad reflection of Bethesda's refusal to grant players the freedom to decide their own character and their own motivations.
What makes it even worse is that they don't really take advantage of the changes they've made and use them to their full potential. For example, they want to give the PC a voice. Okay, then here's an idea - why not hire someone with a distinctive, cool voice for the role? Not necessarily a huge celebrity, but someone like, say, Keith David or Michael Ironside. It makes sense that the character who does the most talking throughout the game should have a voice that we want to listen to. And even the fact that they have a recognizable voice could work in the game's favor as a parallel to the fish-out-of-water setup. Their voice is the only remnant of familiarity the player can cling to in this strange new world. But there was no point in doing what they did, hiring a couple of people with such plain, unremarkable, "I'm just a regular guy" voices without a shred of personality or charisma to them. If they wanted the protagonist to be a blank slate that players can project whatever personality or intentions they want on, then they could have just stuck with the text.
The same thing goes with the Cap/Rip gimmick, which is completely squandered here. Okay, so is our hero supposed to be grieving for his lost wife and son? Then how about his grief informs his interactions with the characters and environment to a much greater degree, rather than only coming into play when the player selects dialogue options indicating his grief for his wife or son? If the idea could be introduced that he's blinded by his grief and desperate for revenge, we'd have the potential for an interesting inner struggle - can the hero keep true to his strong moral upbringing in Pre-War America as he tries to put things right? And even if he can, should he? Or, on a lighter note, they could have focused on the hero's shock and amazement at the wacky new world he finds himself in, rather than, once again, only doing so when a dialogue option indicates as such. For example, we could hear some unique exclamations whenever he sees something crazy for the first time, like Super Mutants or brahmin. It could help provide both immersion and humor.