You do realize that Dannell Harris has been acting since 2004 primarily in the genre that they are gunning to lay over the super-hero film and Katie Cassidy since 2003 being critically acclaimed in many of her roles. Just because they aren't Shakespearan actors doesn't mean they aren't worth a consideration and just because they have appeared in Maxim doesn't mean that they aren't well established actors.
Bryce Dallas Howard is exactly the best actress in the world, primarily passing for okay in many of her roles and let's be honest, the Spider that bit Peter gave more of a deep, engaging and emotional role than Dunst.