The Scrappy: Most of the cast, especially Kevin and his circle of friends. Kevin is essentially a Scrappy Hero with his constant mewling and whining. For his loser friends, Daphne and Kyle especially stand out for their Scrappyness.
Special Effects Failure: The Hobgoblins were basically stuffed animals. Only one was an actual puppet that could have its mouth opened and closed with a hand inside it.
They Wasted a Perfectly Good Plot: Clearly, the movie would have been much better if Dennis, the irreverent music lover, were the hero. This is probably because no matter how stupid his friends are, there's no way they'd be as annoying as Kevin and his pals.