This Q&A with Jason was posted at the Dragonmount forum, after Jason published his review:

Q: "Does the book have some subtle hints to some information that only readers who pay close attention can notice? (Example, in WH observant readers noticed that Anath was Semirhage.) Do you have a theory about one of these that you can't wait to share?"

A: "YES! There is a fairly small mystery that gets introduced into this book. (No, it's not another murder mystery). Actually, it's not even a mystery for the characters. Its just something that makes you wonder 'Wait a second, what's this all about?' I asked Brandon about it and he was very mysterious on his answer. Then, eventually, it hit me like a ton of bricks. I have an awesome theory and I want to see how many other people pick up on it. I'm certain it will make it into the WoTFAQ."

Did Jason mean Rand's sword as the new small mystery, or what? Does someone know which theory he had? (e.g. that it's Justice?)