Ok, feel I've put enough time into FO4 for some first impressions: This is the Fallout game I was worried Fallout 3 would be.
It's something else wearing Fallout's skin. The quirk and charm (even from the third game) are gone, a good chunk of the actual Special RPG system is gone, the dialogue is largely dry and univentive.
While I do enjoy the settlements (more on that later) the need to basically hoover up everything from your environment takes a lot of the fun out of the detail and craftmanship that went into the environmental design.
That said, it's a good game. Great game even. Very streamlined/skinnerboxed, good shooting mechanics, standard suite of systems are there and working nicely, graphics look great. In a lot of ways it feels like a better Arkane Studios game than Arkane Studios has been making recently.
I didn't know how the settlement thing would work but outside of the rage inducing interface Bethsoft really nailed the core idea. Love exploring, clearing, and then settling my own little safe havens across the wastes. Have kept the defenses up and so haven't been dealing with too many "Your settlement is under attack" prompts either. I do wish there were fewer of them and each had a bit more personality (as it stands I suspect the end game is going to basically be settlements every 100ft with patches if wasteland in-between) but I am really enjoying the core concept of finding, gaining the trust of, then managing these little oasis' of calm in an otherwise hostile world.
Naturally the mainline Bethsoft quest is just... ugh... I am getting a kick out of characters like Nick Valentine and there do seem to be some side quests with actual personality (Silver Shroud questline comes to mind).
So it's early, like 15 hours in level 20 early, but I can already feel the cognitive dissonance between "This is a legitimately good 'survival' game" clash with "God damn why did they have to call this Fallout?!" creeping in a long all the edges.