I also would have been inspired to make a great Fallout game using their own engine after playing Fallout 3, just to show Bethesda how it's done.Planet Fallout Interview – Chris Avellone (archive):
What was the main inspiration for the development of Fallout: New Vegas?
Fallout 3.
LOL!
After all, look at what he said on the question before that one:
Notice how Fallout 3 has very little to nothing of that.What, in your opinion, are the crucial elements for a good RPG these days?
The range of character development and customization, and reactivity to that character choice and development within the game world. The more you can do to bring story, world, and characters into the equation, the better, but ultimately, players want to build the character they want, customize their character, and then have the world respond appropriately through dialogue choices, ways to solve quests, or even NPC's reactions to your character's purple mohawk.