Any way you want to describe or analyze them, superheroes, werewolves and vampires are just humans with impossible abilities. It's up to the creator to imbue more into such a silly notion, like creating morality tales out of them. Again, steampunk isn't immune to such a treatment.
So far, the only steampunk elements that have made it to the big screen have been patently impossible... much like shapeshifting teenagers and flying men opening portals into space or turning back time. The only thing lacking has been the execution of each idea, to wit, a Joss Whedon to pull off what a Tim Burton could not.