Too many plot holes and coincidences going on in the ending sequence for the following to be not true IMO. SPOILERS obviosly.
I presume thats a link to the spoiler?Indoctrination theory?
I dunno, man. Bioware said before the game was released that they had spent a lot of time on the ending, and were happy with it. I think that might actually be true, unfortunately for us, they got it horribly wrong. What I wouldnt be surprised by, would be them to run with this idea and implement it into a new/true ending/epilogue.
spoilersFor example, Shepherd being under alot of pressure durnig the final mission, and the injuries sustained from the final attack on Earth making him/her more susceptable to indoctrination.
Regardless of what they decide to do, some DLC is on the way, we know that much, and it was always going to be. They're probably terribly embarrassed at how the ending has bombed, so I don't suppose they'll ever admit that the future DLC was ever going to be an extension of the ending or not. After all, previous DLC that has been released doesnt require you to finish the game before you can play it, so the events of the ending don't have to be taken into account...
I'll be honest, I probably would have bought any DLC despite it being inevitably terrible as the vast majority of the previous DLC was. If they do decide to do another ending, or an extended ending, or an epilogue or whatever, and they charge for it - prepare for the next fanboy shit storm