I actually stay away from guidelines/essays on how to create interesting characters -- not scorning what you've posted here, Elliot, but personal preferences. Again, like what I said about creating complex plots, applying formulae to this could be detrimental. Some people will suggest that you create a character profile: list the likes, dislikes, personality traits, skills, flaws -- but that doesn't work for me, either, since I'm a horrible plotter and planner.
So yes, I do think creating interesting characters can be hard, but if you let them hop around in your head a bit -- even run along with the story -- I think developing good ones shouldn't be too hard. I know that my characters are a lot more solid to me by, say, the fifth chapter than they were when I started planning the story.