QuakeCon happened recently and John Carmack talked on RAGE's flaws. He admitted that the team at id Software handled the game, specifically the PC version, poorly and that they made the game a shell of what it could have been. He talked on the ending, but I will hold that information due to any spoilers that could arise. He also claimed that he does not, despite what he said about RAGE and its errors, want the people to think any less of what RAGE truly was. He did not give any new information about Rage 2 or why the game never received DLC.
Also he announced a Doom 3 BFG Edition and that Doom 4 is in production, but that is a completely different story.