It's no secret that Hollywood fucks up much of what it touches, especially in franchise efforts. Too many thumbs smudge the lens. In most cases the source material is so dreadful that it doesn't matter, save to financial backers. But once in a great while the source is worthy of respect and care, which naturally guarantees the opposite. Better source material is usually an affront to mechanized minds, so it must be dumbed down for the public's benefit. Anything less would be elitist.
Guy Ritchie's Sherlock Holmes is a loud exploding example of this, Conan Doyle's creation rewired to fight Terminators. Hell, if Ritchie had introduced Victorian-era cyborgs, I wouldn't have blinked. They would have been right at home. This Sherlock Holmes more resembles Barry Sonnenfeld's Wild Wild West than the original stories. All that's missing is a big music/dance number over the closing credits.
Being a Holmesian geek, my perspective is skewed. I read Conan Doyle's stories as a kid (alongside the Hardy Boys and Sad Sack comics), and while I didn't understand every utterance or period reference, I embraced the mysteries Holmes was hired to solve. I saw Holmes as a superhero, his Baker Street flat his Bat cave, his use of drugs his spinach. I liked the idea of wrestling with clues and ideas in a snug private space, a conceit that remains, as anyone who's lived with me can wearily attest.
Re-reading the stories over time, I grew closer to cold, calculated Holmes. While I would never presume to match his intelligence, there are traits we share: the obsessive focus on subjects, the sensitivity to crowds and public noise, the use of chemicals to expand/quell the mind, the personal mess and clutter. One major difference is that I would never try to capture violent criminals. I'm too delicate for such excursions.
Robert Downey Jr.'s Holmes isn't quite right. It's a different approach, which is fine, but confused. A disheveled inconsistency. His English accent is slight to non-existent. Perhaps because there've been so many Holmeses, Downey decided to strip his down to nothing. Hard to tell. I'm a big fan of Downey's and consider him a first-rate talent. If Holmes were a new character, maybe his approach would work. But I simply don't recognize the old detective.
Jude Law's Watson is more Jude Law than Watson. And I don't recall the good doctor being so handy with his fists and feet, much less adept at stick fighting. Watson was brave and armed himself when necessary, but he wasn't Kato to Holmes' Green Hornet. Rachel McAdams' Irene Adler is stunningly bad. Adler, "the woman" as Holmes called her, was one of the few who could mentally match Holmes. McAdams conveys nothing of the kind. Her presence is a distraction, which is an achievement considering the other distractions Guy Ritchie has flying around the screen. As with so much else in this film, McAdams is anachronistic -- modern Hollywood playing dress up against a CGI London. The bastards simply can't help themselves.
As do numerous fans, I consider Jeremy Brett to be the best screened Holmes. Brett not only caressed Conan Doyle's cadences, he looked much like the illustrated Holmes, at least early on. Age and weight made Brett's later outings hard to watch, but in the original episodes, his Holmes crackles with intensity and intelligence. Here Watson (David Burke) returns from a trip to find Holmes meditating before a fire. Holmes' thoughts on mental stagnation were uttered by Downey as well, only Downey rushed his lines while crawling on the floor. Brett takes his time.
In Ritchie's film, Professor Moriarty remains cloaked in darkness, doubtless being saved for the sequel. In the Granada series, Moriarty is seen in the light of day, a criminal mastermind going about his business. Here Moriarty invades Holmes' flat to issue a final warning. Two equal intellects ("He is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city. He is a genius, a philosopher, an abstract thinker. He has a brain of the first order") serving different masters.