You hit on all the great points with the subject matter. Your review could stand for my review. I'm going to remove myself from the emotional content and talk in broader terms about King's cinematic contribution.
I grew up watching documentaries that always had an agenda. Today you never see a documentary that doesn't have some point of view behind it. You can blame Michael Moore, but there's Paradise Lost and Capturing the Friedmans and The King of Kong. They're all documentary in form, but manipulated in content. Children Underground was one of the first "true" unobtrusive docs that I watched.
Now along comes Allan King who even brushes aside the label 'documentary' and admits to manipulating his films into 'actuality dramas'. Yet, I don't know the details of what was altered. With A Married Couple you sense some sculpting of bitter and sweet times for dramatic balance, but here it's like no tailoring was necessary. Everybody moves forward towards the same unavoidable conclusion. All King needed was the access and then the guts to not flinch.
I had forgotten the film was 2 1/2 hours. I was so absorbed in these people's lives I never considered my usual crap about how he could've edited out a patient and brought it closer to 120 minutes. A great film is never too long. This film furthers my belief in Frederick Wiseman as an overrated snoot, who goes out of his way to make the footage not connect in any interesting way and whose epic length documentaries are more punishing than involving. (To all Wiseman fans, I openly admit that I've only seen 2 of his films. Both were under 90 minutes and felt like 2+ hours. You watch Warrendale, A Married Couple and Dying at Grace and get back to me. If you still believe Wiseman is better, I'll take a dictation.)
tjwells, let me lower your expectations for Memory for Max, Claire, Ida and Company. I already watched it and it didn't grab me. The major problem is that Alzheimer's and dementia put up a barrier. You're struggling to understand what the people are trying to communicate and they're constantly having to be told the same information. It's a variation on Dying at Grace, but doesn't yield the same interesting results. Just a lot of depressing confusion.