I try to sum it up short. I'd say if you only look at the Mass Effect games themselves, the IT is probably the best and most plausible way to explain all those big plot holes, unability to talk back to starchild and so on. It opens the possibility that this horrible ending did not real happen and the real ending after Shepard waking up is yet to come (even though this is totally mean, of course), so for some time I really believed the IT to be true.
But it has one big problem: Reality. If you go beyond the game and look at our present reality and BioWares statements it's very unlikely that the IT is true. I am not talking about those things like "We won't change the ending, only clarify it" or "artistic vision" and stuff, no, that still could be part of: "Hey man, don't believe BioWare, they are just tricking is, they planned this all along!" but now the thing gets problematic: Why in the world would BioWare still keep it a secret and decide to suprise us later, when they see how many people protest and are even giving back their games - no company which is right now loosing many would decide not to stop this if it had the power (which they would have, if the IT were true, of course).
So my opinion: In the game: Yes, please, anything is besser than the current ending, I totally would accept the IT to be true.
But for reality: Very unlikely.
The sad thing is that BioWare actually could have made one of the greatest endings ever VIA the IT. Just think about it, you play the ending we all have seen and you have all those WTF?!-moments, are angry, sad and stuff. The credits start running. But then, right in the middle of the credits, it stops and the screen goes black. And suddenly you see Shepard waking up!
The circumstances he wakes up differ from what you chose before, like, Destruction = resist the indoctrination -> wakes up in London, squad finds Shepard or something
Control = giving in to the Reapers and get indoctrinated -> either failure or Shepards squad have to rescue Shepard (which actually could give the opportunity to like, play as Garrus to rescue Shepard or something like that).
What I try to say is, it could have been a complete awesome "mind = blown" using this IT, but of course it wasn't, we're all sad and frustrated ("it could have been soooo great!") and have to wait.

But nevertheless, how do you like my idea?