Fallout: New Vegas project lead Josh Sawyer has answered another fan question via his Formspring page. This question, while not phrased as such, directly asks what he thinks about Bethesda's massive changes to the game design from the original series to Fallout 3. Check it out:
Q: Do you think developers should ignore the demands of some hardcore fans to keep obsolete or inferior features in the sequel just because it was in the original?
A: I think developers should try to make a good game. While this means they do have to understand the expectations established by previous titles, they have to be willing to re-evaluate mechanics if they've demonstrably failed or caused problems in the past. I think its most important that they keep the spirit of a franchise/series/world alive. If they can do that while improving a mechanic, they should go for it. If changing mechanics radically alters the feeling of the setting and series, the cost has to be weighed very carefully.
Remember, you can ask him anything you want over here.