Although I think it falters on some of the finer theological points, I found that this review of The Passion echoed much more eloquently my main concern in this way:

There are many other problems, of course, but the cumulative effect of Gibson's "artistic license" [with violence] is that it grotesquely distorts not just the crucifixion of Christ but its meaning. His sacrifice becomes not a gift of love but a loss in war, an act of brutality to feel guilt for, a death to be avenged.

I will also add that the rest of the review is worth reading.