My favorite part of Fallouts past was that the games were truly open-ended. You could go nuts and slaughter a whole town, save for those damned invincible children, who still insisted on entering into battle with you only to spend every turn panic-sprinting to the edge of the map you little sons of bitches. And if one of your victims just happened to be a major quest-giver, well, that's called a consequence, motherfucker. Sometimes your actions have them.
We lost some of that with Fallout 3, which had invincible major characters. Oh, sure, that made for "a smoother progression in plot" and ensured you didn't "accidentally screw your whole game 'cause that guy on the aircraft carrier called your hat ugly so you slaughtered the entire society two hours ago and only just now found out you needed the captain alive to get the last mission to beat the game." You'd think having a few major characters that can't be killed would make the game less violent and more moral, but the opposite is true. Now I know that once I start machine-gunning mini-nukes into a farm because one of the ranchers stupidly rejected my sexual advances, anybody important will just take a knee for a moment, then get back up and give me my quest. There are no real consequences.
That's been happening since Fallout 3. But Fallout 4 adds a bigger problem: I have seen very few opportunities in the game to be anything less than a good guy with a personality problem. That's down to the nature of the central story. In the early Fallouts, and in New Vegas, you were pursuing a fairly neutral goal. In Fallout 3, and now 4, you're looking for a lost family member. In 3 it's your father, and that sort of limits your role-playing options. No truly dark and malevolent character is out there in the wasteland screaming, "Daddy, why did you leave me?!" into the radioactive winds.
In Fallout 4, however, you're after the people who murdered your spouse and kidnapped your child. You are cast, from the start, as the good guy. Sure, you can go all Taken on them and do some messed-up stuff in the pursuit of justice, but at the heart of it you always know you're doing the right thing. And I never thought that would be a problem for me. I usually play as a generally good guy who occasionally responds to rudeness with a Molotov cocktail.
Wait, wait, I've got a super witty response to this ...