IMO, people who are freaking out over the real MCAT being different than the AAMC full lengthss need to realize that those tests are from 2007. Think of all the prep books, new editions and whatnot, that have come out since then. It's not like the prep companies have inside access to AAMC (I think), so where do you think they get the information that "such and such is high-yield, definitely know this, they always ask about this"? Those kinds of questions and passages on the AAMC full-lengths seem easier and familiar because the prep books ask a lot of those same questions, and so some of the unpredictability is lost.
In 2007, when those were actual MCATs, the people taking them didn't have the prep material we have now, so saying they were easier might not be entirely accurate. And I know that people will say that certain things are inherently tougher now, like the experiment-based BS section, but remember that that's not true for everyone. I personally find it much easier to find answers that were already given to you in the passage than remembering 1 billion bio facts.
Also, are the AAMC's supposed to be a perfect indicator of the real MCAT? It feels a bit entitled to me, to scream about how that practice stuff is worthless because it's not exactly like the MCAT. Are all your professors expected to give you practice exams? Why expect this for the MCAT?
HOWEVER, if the AAMC actually advertises that it is exactly the kinds of stuff you will see on game day, I take this back and say that is their fault for false advertising.