All of those elements can be explained away with just plain shoddy writing, too. Anderson's lack of control was because the newly "improved" Illusive Man had some kind of psychic control over him. You notice this as he is released and falls to the floor immediately after TIM puts a bullet in his own head. Anderson then dies because of his injuries before getting to the Citadel, and Shepard having shot him while under the control of TIM/Reapers.
Apparently a very early version of the script had a similar, but much expanded, ending -- the "destroy" option of which had Shepard miraculously thrown from the explosion and returned to Earth by the conduit. Hence him waking up in the rubble... it's not an indication that everything was an hallucination. Rather, it's just a literal continuation. The Citadel was destroyed, and Shepard was blown back to Earth through the conduit, awakening "victorious" amidst the interplanetary decimation he's caused.
Recent statements from Bioware -- Casey in particular -- have pretty much said outright that they were happy with the ending and its handling of the ongoing themes of sacrifice and desperation. That's telling me that it is indeed a literal ending. Shepard isn't waking up from an indoctrination attempt. He's waking up after destroying half of the Universe through a cackhanded deus ex machina survival.
Ultimately, within the next 30 days I reckon we'll see. Bioware only have so many cards to play, and they can't keep silent forever. Another factor though, is if they fully intended to release a DLC finale... what about all of those fans across the world without internet connections? There's far more of them than you'd think, and they're stuck with the steaming pile that's left on the disc. There's no way a company would take such a commercial risk. It's suicide. But then again, so was the ending, so go figure...
Unless Mass Effect 4 is announced, and the story picks up with Shepard awakening in that rubble after what was indeed an indoctrination attempt to continue the fight against the Reapers, and Harbinger in particular, I believe we're just going to have to look fondly at all three games on our shelves for the forseeable future, and try to swallow the mouthful of vomit that doing so will undoubtedly prompt from this point on.