There seems to be a general softening of opinion based on this preview, and that's interesting, because I'm having the opposite reaction. I now know with absolute certainty FO3 is a game I will never play.
My primary objection is that the entire project reeks of unimaginative sequelism. It's the same simple-minded idea that plagues second-renditions of nearly all games and movies: everything that was popular the first time around must be made bigger. In the original FO games, there were super mutants; since FO3 is a sequel, we have to have Super Duper BEHEMOTH Mutants! In the original FO games there were rocket launchers, so FO3 must have ATOMIC BOMB LAUNCHERS! This is despite the fact that, logically speaking, there ought to be fewer super mutants as time passes, and that the whole concept of a nuclear bomb catapult is, frankly, absurd. It reminds me of Pirates of the Caribbean - that unexpected little gem of a movie - and how with each sequel it became less and less about pirates or the Caribbean and more and more about bigger, flashier special effects and supercool plot twists until by the end it was just a convoluted mess.
Second, the fact that the people making this "sequel" are not the people who made the original means the player, provided he is familiar with and enjoyed the original material, is going to be surrounded by a pseudo-milieu: the product of lesser minds or lesser inspiration aping the original vision. Is there anything more icky? Consider the humor. Original FO has a quirky, nerdy, unusual sense of humor with roots in the computer geek community of the 1980s. The original FO people managed, as a group, to capture that spirit and make it work. Now imagine some one who isn't funny in that way trying to imitate that sense of humor. For those of you who aren't already in pain, I'll try to illustrate the concept more effectively. Think of your favorite comedian or comedy - for me it would be Steve Martin's standup from the 1970s, and Monty Python - then try to imagine some one else trying to be funny *like* Steve Martin or *like* Monty Python. It's...ugly. That's what you've got in FO3. A sign that says, "Local Cult?" Under the circumstances I find that incredibly un-funny.
Third, FO3 suffers from the greedy selfishness and arrogance of Bethesda's need to own the setting. The only reason it's set in D.C. is because that's where they are; there's no other good reason for a FO game to be on the east coast of the U.S. I see lots of destroyed buildings, but where is the desert? Where is the Wasteland, for crying out loud? They've amputated a big chuck of the FO setting that goes back at least as far as The Road Warrior: the wasteland.
This preview has changed opinions because it is the first skeptical, objective assessment of the game. It's changed my opinion for the worse. The intellectual content is going to be lackluster. If the intellectual content isn't great, what good are sparkly new graphics? There have been a thousand games with better graphics than FO, but how many games have been better than FO? If I want to waste my time with a FPS, I have a whole slew of options that won't be irritating me by mimicking something I liked, but they're incapable of understanding.