Making Tony Stark an emotionally crippled fish-out-of-water and forcing him to MacGyver his way out of trouble is just so compelling. It's a classic formula: bring a powerful protagonist to their knees, actually break their knees, and make them claw their way back. If done right, it never fails.
And the Mandarin, damn...it took huge balls to commit to that sleight of hand. I loved it. If the chances you take are smart, they will most likely work out, even if you cause a little nerd rage along the way.