If you take a look at some of the recent screen shots for Bethesda's newest entry in the Fallout series, you will probably notice that graphically, not much has changed since Fallout 3. This is due to the fact that the game runs on the same engine used in Fallout 3, and in many respects, the textures, artwork, and animations remain the same. This may upset some, as New Vegas could potentially have been released as an expansion for Fallout 3, as opposed to to a full priced standalone game, but development has changed hands in such a way that I will gladly pay up.
The original Fallout games were developed by Black Isle Studios, and they allowed for much more freedom in both action and morals than the Bethesda developed Fallout 3 was able to provide. Fallout 3 was a great game, but it ended up feeling diluted and restrictive regarding matters of character choice. Interactions typically fell to combat, whereas in the first two Fallout games, you could use civilized conversation, infallible logic, proven science, or if absolutely necessary, a cheap shot to the groin.
While Black Isle Studios was dissolved, many of its employees now work for developer Obsidian Entertainment. Backed by Bethesda, serving as producer this time around, Obsidian Entertainment has been given the Fallout 3 engine to do with what they will, and from what I have seen so far, every complaint I had about Fallout 3 has been addressed.
The V.A.T.S. targeting system has been revamped to not only include groin shots once again, but special weapon specific finishing moves as well. The diversity of character interaction has increased, and those that choose to specialize into the social aspects of their character will see much greater rewards than those offered in Fallout 3.
Another issue I experienced with Fallout 3 was the overall dilution of my character as I approached max level. You ended up literally having every skill in the game, with the only real variance being in what order you chose to max them out. This has supposedly been fixed in New Vegas, with characters becoming very specialized depending on what skill route they choose.
I can't wait until October 19th, when Fallout: New Vegas is released in North America, for I shall delve deep into the man cave and return enlightened by the developmental power of Obsidian Entertainment. If it does end up sucking however, you can call me out on it here.