NOT EVERYTHING needs a reboot. There's a good reason the James Bond franchise got a wildly successful restart, and that's because (A) they wisely cast Daniel Craig, and (B) the James Bond franchise had become rudderless and terrible. I don't recall anyone saying, "Wow, why doesn't someone make a new, more exciting Sherlock Holmes?" That's probably because the world isn't exactly clamoring for reboots of stories from 19th century authors (Clueless notwithstanding).
And yet? Here we are with an "edgy" revival of Arthur Conan Doyle's most famous character, starring Robert Downey Jr. as the eccentric detective and Jude Law as steadfast sidekick Watson. Both are fine choices, since their scenes together crackle with energy and camaraderie. And while Guy Ritchie (Lock, Stock, and Two Smoking Barrels; Snatch) is an unusual choice for what is essentially a period drama, his direction does at least provide an incessant (if unneeded) energy to the proceedings, imbuing turn-o'-the-century London with a ratty, violent, lusty backdrop.
Serious problems arise in two areas: The first is Downey's nonstop mumbling, which renders Holmes' enjoyably wordy deductions nearly indecipherable. (Fortunately, Downey's so charming that it's hard to get too upset.) A more pressing problem is the script itself, which, in a desperate attempt to be relevant to a modern audience, forgets why the original texts are such a kick. Doyle's stories (and their terrific adaptations, such as the 1984 British TV series starring Jeremy Brett) are entertaining and cerebral, allowing the reader/viewer to work out the puzzles as the plot unfolds. This Holmes, though, drops in only occasional aspects of the original, sandwiched between chase scene after fight scene after disaster after explosion, forcing the viewer to surrender their role as participant. It's boring—if I wanted to switch my mind off, I'd rent Transformers.