Of course I'm not a hater, just a little disappointed that's all. And I realise these are all just opinions in either direction, however I think it's important to critique games like this when anyone feels like they have a legitimate cause to critique them - if for nothing else that the devs might take notice and introduce things that make the game more enjoyable to a broader audience if enough people feel like this is an issue. For future DLC for example, they might think of a way to work in a system where the player is more free to do as they please.
And again, I get that you are physically free to do as you feel, but in an abstract sense because you are supposed to be a caring parent you aren't made to feel totally free. It's more abstractly confining because parenthood is a big deal and a huge responsibility, the responsibilities placed on the player's shoulders in FO3/NV/Skyrim are much smaller and so more readily put off. In all those games I can play as an uncaring [censored] if I want; in FO4 you can't because whilst you can physically ignore your son you can't escape that, because you have a voiced character and Bethesda chose to make your character mention Shaun a lot, there's no real way to access the same range of personality types you could play in previous games.
In terms of the how long have I been frozen question conversations with Valentine make it clear that your character believes he was defrosted very soon after Shaun was taken, and it's only Valentine questioning this which really allows the idea to figure in your character's head. As such this ties back into to the sense things are pretty urgent, at least until Valentine puts that idea into your head, and even then it's only speculation.
To be clear, I did go and explore and scavenge and get set up, but in the end I think there's a much greater pull to do the main quest and I don't feel I explored as much as I would have liked because I felt obligated to go search for my son to maintain that internal consistency necessary to actually role-play a character. If my character hadn't had mentioned him so much, I would have felt more free to continue to do exactly what I wanted in the game - and seeing as I wanted to play a brutal, drug addicted cannibal who had substance abuse problems before the war and didn't much really care for his family I couldn't fully realise that character in the same way that I could in FO1/2/3/NV or Skyrim for that matter.
And in terms of "[y]ou seem to want the ability to play a game according to the vision you have for a character -- and have the game react meaningfully -- and have that reaction be the one you want and expect" - it's really only the first of those three I want, to make a character completely in the vision I have for them without anything already ascribed to their personality like you have in FO4 (you are always - always - the caring parent). Having a game react meaningfully to you doing stuff in a game is kind of a given for any game to be enjoyable, the game reacting in a way to actions of my own choosing as I want or expect isn't at all necessary as it's nice to be surprised.
I think, getting to the crux of the matter, the factions in Fallout 4 have too narrow goals to make me like them so much or to make them applicable to a dearth of different personality types and hence roles you want for your different character. With the Railroad, you kind of have to make a character who's going to want to help out the synths, with the NCR in New Vegas you could play any character who likes democracy.
Because New Vegas factions tackled many more of these real world problems of governance that still face many countries today, I think it was much more relatable than "Oh we want to save the Synths" or "Oh we want to get all the tech to save the world from itself". They just aren't very directly relatable to real life, and as the character is fresh from before the war the game is asking you to develop strong idealistic sentiments more or less off the bat for a variety of causes that weren't much in existence pre-war (some, like BoS, you could argue might overlap more with your character's feelings from before the war that technology is dangerous - others like the Railroad are more or less asking your character to care without much pre-exposure to their niche issues).
I also do think that the way the factions in FO4 are very focussed around specific goals makes them more one dimensional than New Vegas where they concern themselves with abstract ideas of governance and the like. This is of course my opinion, and one that really isn't getting any traction around here.
As I said Fallout 1 and 2 weren't in anyway under Bethesda's control and so they didn't necessarily shape the narrative choices in their games, and as Bethesda has since made the decision to not have a ticking clock narrative like in 1 and 2 as seen in 3 and NV (which of course was Obsidian's baby, but I'm sure Bethesda would have signed off on the general choices they were making) we can assume that what they choose to do with their narrative structure is not a reflection on the previous members of the series.
Having said that, let me tell you how you're wrong. In Fallout 1 and 2 you're given very loose timelines in which to complete your actions (months) to find what you're supposed to, and you're told this from the start. While yes, that makes it a ticking clock narrative, that clock is ticking pretty damn slowly and you've been told from the off that's the case, plenty of time to do some exploring. Further in Fallout 1 and 2 it's a responsibility that's been off-loaded onto you and so one which you might try to ignore and resist, in Fallout 4 you want to find your son.
Now Fallout 4, your son in your mind has just been taken (as I mentioned to Plebeian, when your character talks to Valentine he seems entirely unaware that things happened anything but instantly). Your character vocalises upon seeing your partner's dead body, "I'll find who did this, and I'll get Shaun back. I promise." (Yes I bothered to check). As far as you're aware every minute that you spend not finding your son is a minute that he's getting further away from you - the very definition of a fast ticking clock narrative. Is it in Taken where they give that statistic of people who are lost for more than 24 hours become increasingly more likely to not ever be found? Now put that situation in a wasteland and it only gets worse.
Given that your character has vehemently promised to find your son, how do you justify going off on a jolly around the wasteland and directly ignoring the leads you are given - ignoring that promise you made moments ago to your dead partner? And if you talk to anyone, as I mentioned there's many instances where talking about Shaun and your desire to find him is unavoidable (Codsworth for example, but many others too) further committing you to the idea that your character's chief motivation is finding their son. Sure we can just ignore the son and not see it as an issue, but because your character professes to it being such an issue it's damaging to the consistency of how you play that character in that you're defying the thought processes about how you feel about Shaun which you vocalise. And in the instances where you don't directly mention Shaun ("Why are you doing this?" followed by, "That's my business,") as players we still know that he's doing these actions because of Shaun so it really doesn't matter - you're serving that motivation nevertheless. I guess maybe you're not bothered about narrative inconsistency, or playing a character with some internal consistency.
FO:NV and FO3 simply do not compare in terms of having a ticking clock. Sure if you want to play a character who cares deeply about his profession and wants to get the chip back at all costs then it's urgent, and maybe if the character had voiced, "I'm going to get that chip and deliver it at all, I promise," I could see your argument - but the fact he doesn't means that it truly is only urgent if you want to play it like that and you do have freedom to do and interact with whatever you want. There is no implied urgency to your quest like there is in FO4, and when people ask you why you want to catch up with Benny you can answer in a number of ways implying a variety of different motivations (Veronica is a prime example of this, the first dialogue with her). FO3 is much the same, you're character never lays down a promise to track down his dad (at least, from what I remember) and so there's no urgency.
Can you really, really not see the difference here? How Fallout 4 is providing you with motivations whereas Fallout: New Vegas and Fallout 3 let you create your own, and how those motivations if you do want to play true to them are restrictive in doing what you want? And even if you have strong similar motivations in 1 and 2 (and I'll stress, I don't think their narratives are relevant to this discussion as Bethesda are now in charge), do you not also see that the implied timeline of what they're asking you to do is very different in terms of scale - allowing your character much more time to explore and grow as a theoretical person? And further, that in Fallout 1 and 2 your character never actually promises to do the thing they've been told to do, and so might mess around if they didn't really care for their respective communities?
As I have said I get time and time again that you can physically shirk what your character says is the most important thing to them, however it is inconsistent with the role of caring parent we have been given and the point of me playing a role playing game is I want to play the role I'm in well. If you really can't see how there was a difference here, and why I don't like it especially when Bethesda made games where they didn't do it in the past, then I won't bother getting into it any more with you. I won't however accuse you of being a liar and all the other nonsense as you have done with me, sir.
So a faction that is essentially freedom fighters for robots (saying they don't do freedom fighting for others really doesn't make them more complex) is more complex than a faction of neo-Luddites who use brutality but don't actually care for that brutality beyond using it as a means to an end to achieve a strong dictatorship, and have selected fanciful iconography of the Roman Empire as a means unify a population under a single banner through patriotic jingoism. These factions are equally as complex? And just exactly how many character archetypes do fit into the Railroad, beyond freedom fighter? There's literally no reason to join them and invite trouble other than if you believe in their cause, the same is not true for the Legion who you can merc for or join because you like their brutality.
You're again going to be entirely unconvinced, so I'm not going to bother going at this anymore unless you cared to take and a different tact and be less rude. Most of my other feelings about the factions are already summed up with Plebeian earlier in the post. I never said what I'm saying is fact, and to be honest you telling people that I'm spreading lies and misinformation only serves to weaken your argument by making outrageous claims - but I guess if that's how you like to discuss things, by getting needlessly heated and insulting, that's your prerogative.