Your feelings on the new Sherlock Holmes movie will probably mostly depend on your feelings on superhero movies in general. Make no mistake: Sherlock Holmes fits squarely in the superhero genre that we've all become familiar with over the previous decade. Holmes, of course, follows the Batman model (basically human and theoretically--if not practically as the title character in a movie desperate to spawn a franchise--mortal) more closely than the Superman model (not human and not really mortal); his specific power is a big brain. That's a slight shift from the usual superhero fare but it's one of detail rather than overall direction. Holmes still gets to save the girl, and defeat the villain (on top of an unfinished bridge, suspended hundreds of feet in the air, no less), and frustrate his sidekick with unnecessary risk taking, and dedicate some time for comic relief (nothing's funnier than a flatulent dog), and set the stage for a sequel.* I might be bored with movies in which there's no possibility for anything seriously bad to happen. (The most egregious example here is Watson's unexplained survival of an elaborate three minute explosion sequence.)
*Sherlock Holmes has already earned $228,975,000 worldwide according to Box Office Mojo, so there's no chance that a sequel won't be made, but I think it would be fun to track movies that obviously set the viewer up for a sequel but fail so spectacularly that one is never greenlit. Just a small bit of schadenfreude directed at overconfident directors.
But even if you're not yet bored with superhero movies and conventions, your enjoyment of Sherlock Holmes will also depend on your enthusiasm for Scooby-Doo-style storytelling techniques. This is because the plot of Holmes precisely follows that of an episode of The Scooby-Doo Show. The mystery is established, Holmes or Fred (or Velma or whomever) acts counter-intuitively to defeat the villain, and the rest of the movie/episode is spent explaining the mystery. In Sherlock Holmes, the good detective pauses every twenty minutes or so to explain to Watson--or, less plausibly, to the bad-guy--why he did something and how he saw through the deception. An awful lot of Robert Downey, Jr. explaining things goes on in what is supposed to be an adventure movie.