Worst Case Scenario for Xbox Durango?

There is a possibility the new Xbox won't be able to:

  • Play games without an active internet connection/offline (can't see this being extended to the blu-ray drive for movie/DVD playback, but you never know) even if the game is single player and/or in campaign/training/local multiplayer mode.
  • No backwards compatibility (looking like 360 games, original xbox games should be able to work via emulation - similar to how later gen PS3s can play PS1 games but not PS2).
  • Unable to play used games

Which rumor is most/least likely? Which one, if any is the "killer blow"?