Rewatching scenes from the film for the umpteenth time, this time in crystal clear HD, I am even more in awe of the tremendous special effects work, but most of all of Sentinel Prime. He is without question one of best designed Transformers ever, and sets the standard for movieverse style intricacy. His face is capable of so many forms of expression- during his revival scene, his eyebrows cock, he smirks, and he shows confusion just as effectively as a human being. ILM really outdid themselves in emoting the character, when he above all needed that emoting. Which gets me to the second point of this thread, why Sentinel as a character was a terrific thought on the filmmakers' part. DOTM really worked as a sequel because of raised stakes not only with the Decepticons' master plan (which, unlike in ROTF, felt threatening because we actually got to see it in action) but because the plot challenged the characters on an emotional level. With Sentinel Prime as a leading villain, they could in turn explore Optimus much further, and see just how affected he was by the betrayal of the one he trusted the most. That was one of the factors that made DOTM such a satisfying conclusion, and a great sequel.