They could've used the engine that was used for Fallout: Tactics, which was one of the more recent in the series and still managed to hold onto the things that made Fallout great. I understand there is big hype for 3D graphics and all that, but we also had the floating heads for dialogue, the videos, the interactive dialogue trees, etc. And from what I understand about F3, they aren't using most if any of that. Not to mention 3rd person RTS/Turn-based games (Warcraft, Penny Arcade's ORSPD, Paper Mario, etc) are still huge today regardless of the presence of 'new audiences'.
I dunno Letho, you may not be able to please everybody but if you're in a business that caters to others with entertainment, it is your responsibility to make a game that most want. Especially if it's part of an age old series that has become legendary. Now it just seems F3 has attracted people who've never played it before, optimists, and bad critics.
But, let me reiterate some of what I had said about the gameplay and what not. BS has a creative license to do what they please with a game. They want to make it 3D? Fine. They want to make explodable cars that have a cheesy minature nuclear explosion? Fine. But when they gut the traditional gameplay, black humor, and various nuances that made the games great all you've got left is a shriveled husk casing the illusion of something that could've been a great game if they had just chosen better with what to upgrade or throw out.