The Little Things 2.0

Exactly.  Who trusted the Reapers that, in some fashion, they didn't really want to destroy us?  Saren.  Dr. Kenson (and her team). TIM.  Those people were all indoctrinated.  What they came to believe also can't be trusted.  Since the Catalyst is ultimately behind it all, it can't be trusted.

Unless, it's the Catalyst who doesn't exist at all. An image conjured up by Shepard in his/her own mind to represent an internal debate about the various options available to him/her.  Shepard is completely alone and mortally wounded and faced with a decision that will impact everyone in the galaxy.  It seems logical to me that he/she would conjure up an image from the past in order to sort out the various options available within his/her own mind.

I agree since Shepard is never given the option to ask if it knows what the catalyst is.

Sounds more like a case for IT. I mean, that's more or less one of their claims that the Catalyst was all in Shepard's mind.

Leviathan never mentions catalyst. It says intelligence. Does Leviathan know that the catalyst is part of the Citadel? Don't know because Bioware decided that it wasn't necessary to ask if it knew what the catalyst is.

If it's just hallucinations how does Shepard know what choices are going to lead to what resolutions? I have a hard time believing there are buttons saying "Destroy", "Control", and "Synthesis". Even if they were there, how would Shepard know what they did? It's seems clear Shepard knew Synthesis would lead to death, Control would lead to being a Reaper and Destroy would end the Reapers. Reviewing one's life just doesn't work here. Too much of a stretch.

There aren't buttons marked "Destroy," "Control" and "Synthesis" though.  There never were... the Crucible thing was built to either fire or not fire.  The reasoning is not a stretch since destroy is shown by Shepard continuing to fight, fire his gun at something... following Anderson.  "Control" is represented by following TIM, and Synthesis is represented by throwing down the gun and running towards his/her own path, which happens to be down the center between the other two choices.  It can all be said to be Shepard sorting out what he/she believes in (which was the game journey we were always on) and Shepard never really getting to do anything that impacts the galaxy.  If the Crucible is fired, it is because Hackett figures out a way to fire it remotely.

This is why I like the original ending better... because we weren't given the various post-ending visions.  Shepard dies or completely loses consciousness never knowing what actually happened with the galaxy.  Even i the last breath scenario where Shepard could live and eventually find out what happens, we were not told what happened (so then Bioware could have continued the story however they saw fit).  The EC ruined that.  In giving comfort to some of the fans who seemed to need to be spoon fed an ending that justified their choices, it sacrificed the ability for Bioware to just create a post-war galaxy in whatever form they saw fit.

well even if Shepard did, I do think many versions of Shepard will think  it is a bad idea.

I'd actually recommend you uninstall the EC temporarily and play through once using just the original ones to see if that changes your perceptions at all.  Keep in mind that I'm not trying to convince you that the synthesis ending is a good one or that your individual Shepard would have chosen it.  However, in the context of a dying person weighing both the pros and cons of a situation, could your Shepard have recalled such imagery from the information he/she had discovered and experienced over the course of the three games... a dying person who knows that he/she will never actually be able to make the choice itself... they still don't really know what the Crucible will do even if Hackett figures out how to get it to fire.

I don't think I have any more to say on it actually that hasn't already been said in lots of other earlier threads.

I do consider the poetry themes intertwined with the story to be a significant "little thing" that shows quite a bit of attention to detail on Bioware's part.  As does the "ascension" imagery present in the ending (including the ray of light that was subsequently removed by the EC).

I was thinking about the one when Shepard is passed out on the platform as it is "ascending."  Is it still in there after the EC?  I'll have to fire up a ME3 ending file to refresh my memory, but I though the EC removed it.