http://www.metacritic.com/game/pc/fallout-4
As reviews are rolling out, I'm seeing the same theme echoed through most of the criticisms. Fallout 4 is safe. Fallout 4 is what you expect and nothing new. Fallout 4 also happens to suffer from bad performance, ugly textures, and terrible companion AI like its predecessors.
While none of the last points are surprising, it is worrying that many of the reviews seem underwhelmed by the game. BGS' games are never perfect, but they usually always offer something new and revolutionary the last game didn't. Oblivion had Radiant AI and Oblivion gates. Fallout 3 had VATS. Skyrim had Radiant Story, dragon fights and shouts.
This time around we got a voiced protagonist, solid shooting controls, in-depth crafting, and settlements. Overall, opinions on the voiced protagonist seem to be mixed. Some love it. Some hate it. That was expected. Everyone seems to like the new shooter controls and crafting. Settlements seem to be more mixed with BGS not adequately explaining how they work and function.
I've also read that the story has questionable pacing and the ending is disappointing. Either way, the trend through most of these reviews is Fallout 4 isn't all that different from Fallout 3, and I think to some degree that's an issue when we are seven years later and Fallout 4 is supposed to be the "next gen" version of a BGS game.
Usually BGS always tries to push boundaries in major ways with their games. This time around, Fallout 4 seems to be more of just an upgrade and not really anything that is blowing anyone away.