I saw this movie right after Christmas and really enjoyed it. I have read all the original Conan Doyle works and when I first heard about the movie I was really excited. As I heard a little more about the production, I got worried about it being too silly. Those fears were completely aleviated. I really enjoyed the movie and would like to see a sequel.
Robert Maxwell, I really have to disagree with many of your points.
Watson's engagement: an amusing little side plot at first, though it got surprisingly little development through the course of the movie, and was thin enough perhaps it should've been left out.
Watson's engagement was the entire reason for him to move out, and for Holmes to act petty about losing his only close friend. It was one of the major points to Holmes' character and the Holmes/Watson relationship.
Rachel McAdams: her portrayal of Irene Adler was quite compelling, but again, came off as somewhat underdeveloped.
As one foil for Holmes and as a setup for the sequel, I don't think she was underdeveloped for this movie. This was Holmes/Watson vs. Blackwood. Furture movies will hopefully provide more info on Holmes and Adler, and Moriarty.
Blackwood's plot: kind of a dull, run-of-the-mill "hahahaha gonna overthrow the government!" sort of thing. Could have been saved by having a compelling villain or at least an interesting motive. In essence, Holmes needs an adversary worthy of him, and Blackwood just wasn't it, and the performance was lacking, too.
I sort of agree. But I think that Blackwood was a good villain, and that Strong played him well. His focus on the supernatural was a good opposite to Holmes' deductive reasoning. But he was never really, despite the trailer's editing, meant to be Holmes' nemisis. He was a villan who thought he could confound Holmes while taking over. The real threat lies in the future with Moriarty. Comparing this movie to Star Trek, I thought Strong/Blackwood was much stronger than Nero.
Action scenes: well-done, but started to feel repetitive. I don't think it was necessary to show Holmes planning out his attack and then showing him execute it. You basically see the same thing twice. Just felt redundant to me. Some of the action scenes were very good, and some of them left me cold. I think one-third to one-half of them could've been trimmed in order to round out the story better. Each scene had a purpose, at least, but some seemed to go on too long and I just got bored.
I liked the method of getting inside Holmes' head to see how he puzzles things out, and I would like to see more of it outside of a fight, but I felt the two uses of it were not over the top. The one thing I would like to have seen improved was the editing and balance for the fight in the red-headed midget/dwarf's shop. Watson's side of the fight just wasn't that clear to me. Holmes seemed to be the focus of the scene with just enough shots to show that Watson had dispatched his quarry (until the last saving action by Holmes).
About the only plot issue I have is that there was no resolution to the death of the American Ambassador. We see him die a spectacular death, but there is no indication of the police reaction to it. Holmes is never shown the crime scene, does no investigation, and we didn't see anything like the police's bafflement over the cause of death. But suddenly at the end Holmes refers to it and has figured out the cause of death. I wonder if that section was cut for pacing reasons and I hope it will be reinserted on DVD.
I also have an issue of the cyanide mechanism. It would seem like a very easy trap to "break" if not diffuse. Break the air duct, break the glass, break the "radio" reciever. The only reason there was difficulty was that they wanted to keep the cyanide capsules intact. Could Blackwood not have put it behind a wrought iron grill that was then welded into place. A fine enough grill would prevent bullets from being used to break the mechanism, Holmes and Adler would be kept at a distance from the machine, and the whole "using my pipe" to burn through the weld would have worked just as easily on the grill. Maybe I missed something crutial about the "boobytrapped" mechanisms preventing disarming the device; if I did, someone let me know.