Just finished the game, and I can't really see where all the backlash is coming from. I'd always like more, but all options resulted in the threat being ended and the survivors seeing hope on the horizon. A better future.
As for the theories, I feel I need to point out a few things.
1. Paragon isn't good and renegade bad, paragon is the goodie-goodie nice hero who won't sacrifice the one for the many while renegade is the bleep-this-I'm-taking-the-shot guy. As such both shooting The Illusive Man and blasting the Reapers (along with the geth and EDI) WAS the renegade option, that's not backwards. Sacrificing yourself so noone else must die WAS paragon, no matter whose idea it was.
2. You disregard the very possible scenario that the slow movement was there to add a wounded feel to it all, walking on will alone. Nothing left to give, but unable to give up.
3. This one is probably the biggest argument I have. It didn't happen. Would have been a good show if it did, but it didn't. Shepard didn't wake to be told it was all a dream, he didn't do anything after that. The story ended. If this was all a ruse, we'd have seen its effects, but we didn't...because it wasn't a ruse.
But really, I liked the game, just like I liked KotOR, ME, DA, ME2 and DA2. Could it have been better? Sure. But I liked it. Had a bit of a 1984 feeling at the end where my wishes changed as the mission went along. I wanted to win so we could all get back to our old lives. Then I wanted to win so we could repopulate Earth and rebuild. Then I wanted to get people safely away to start over elsewhere. And finally I just wanted the damn thing to end, not really caring how.