Thing is that Bethesda only has so many employees and only so much money they can use, which means they need a deadline, which in turn means they only have so much time.
If they exceed the resources needed they need more money, if they extend the deadline they need more money.
That is my issue with the idea of post-game gameplay.
Money.
Bethesda don't like taking risks because they need to gain profit.
They like playing it safe. Developing post-game content is a big risk with a game like Fallout, and I don't think they can do it.
Obsidian planned on having post-game gameplay and portray the changes accurately, but they didn't have time, so they had to cut that idea.
But look at what Obsidian managed to get into a game within a year and a half.
Bethesda couldn't get that in 3 years.
What makes anyone think they'd be capable of producing anything even remotely similar to New Vegas
and (Not "or") post-game gameplay where the choices are accurately portrayed?
If Obsidian is doing Fallout 4 and they have 3 years I'd be more in favor of the idea, I would still be skeptical towards it, but I'd be open minded to it.
Bethesda though? I can't.
Thing is i wasnt warned b4 i completed that game first time...
... Yes, you were, right before you start the final quest a pop-up is handed to you on a silver platter explaining that it is the point of no return.
If you chose to just click past it then the fault is on you, not them. They should have to play some tune and have the window unclickable for 10 seconds while bright lights flash around it with the text "this is the point of no return" being in bold and red letters.
If even advices you to save prior to it.
You got a pop-up, that is more than enough.
In Fallout 3, we didn't even get that when we entered Project Purity at the end.