As far as this film fits into the Saw canon, we get payoff on the relationship between Hoffman and Amanda. We also learn of the secrets of Amanda's letter. We also learn about the box that the deceased John Kramer (Tobin Bell) left for Jill. There is a lot going on with these characters and it is interesting to see how they make everything fit together, roughly or not.
I have criticized the Saw franchise for the way the writers try to force every little thing to fit into some perceived grand vision. The thing is, I think what they are trying to do is to be commended. How many other long running franchises have attempted to have as much of a continuing story as Saw? Sure, others will carry elements throughout their run, but I cannot think of any whose tales have been quite as intertwined as those of Saw.
While the big picture is to be commended, it is not the entire story. If all each film did was further the big picture I doubt it would have lasted this long. Granted, this is not a series to jump right in the middle of, but that aside, each film has its own internal tale to tell. In the case of Saw VI, I think it has one of the better stories to tell, helping make it one of the better sequels.
For the first time a Saw film has integrated some real world issues into its bloody mix of gore-drenched traps. You see, when John Kramer (aka Jigsaw) was still alive and fighting his cancer, he found a treatment that could have saved his life. Do you see where this is going? Can you tell what real world issue is front and center? That's right, health care and insurance. Kramer's denial of service sets up this film's primary trap. In a way, you could probably argue that this is in favor of public health care and twist the movie into Obama propaganda. I am not going to get into that, but it could prove an interesting route to examine upon future viewings
In any case, this real world issue and the way the trap is set combined with the people involved made this film all the more interesting. Now, take the real world thoughts of slimy insurance bean counters, the desire of all for health care, and mix in an elaborate series of blood-letting traps and you have a solid mixture for an entertaining film.