http://planetfallout.gamespy.com/articles/interviews/1930/Planet-Fallout-Interviews-Josh-Sawyer
I think that Broken Steel, like Josh says, made the endgame states minimalistic in order to allow post-ending gameplay. Your actions didn't really change much.
Agreed.
Obsidian has stated they have no intention of adding dlc like Broken Steel. If there is going to be dlc it will be set before the end of the game.
What I disliked about the ending of Fallout 3 was that there was no information about how your choices in the gameplay out besides the BoS and the purifier. No matter how long I wandered around, I didn't see any changes from my choices in Oasis, or Arefu, or Rivet City or Big Town. There wasn't any point in the wandering around. Nothing changed. While it was nice to get the chance to destroy the Enclave, it was, for all intents and purposes, pointless. Nothing changed.
If the game is well done, the story is told well, and the ending is detailed and ties up loose ends, it is fine if it ends. That story is told and done; now its time for the next one.
Actually some of the problems that people have with Bethesda's ending to FO3 happened because they were trying to give people what they wanted. Originally the "Lone Wanderer" was supposed to be the *Lone Wanderer*. No companions. People started complaining about wanting companions. So Fawkes, Charon, and the robot whose name I can never remember were added as companions rather late in the game cycle. And suddenly the ending of the game seems rather foolish instead of dramatic. If the choice was between your character and Sarah only, it makes a lot more sense that having a supermutant who is basically immune to radiation, a ghoul who is healed by radiation, or a robot that can simply ignore the radiation standing right next to you when you have to make a choice of who gets to push that button.