Good beginning of an idea. Some very very basic skills should be required in a tutorial. These challenges need to be divided up into tiers however. How retarded would it be to be a new player and come up against a platinum smurf in challenge #11. The possibility for this type of abuse means that there is no way #11 should ever be requisite. It could only be an advanced bonus challenge. Really, any of the challenges that pit you against other players wouldn't be considered a tutorial of requisite skills.