I didn't know Team Preview was an official term complete with capitalization. NBC: The more you know
Anyway, I have kind of mixed feelings about how they leave casual players somewhat in the dark on EVs and IVs (especially in relation to Hidden Power). Imagine if they had to explain how to get a certain Hidden Power on a Pokemon? On the other hand, they probably assume that people are resourceful enough to use the internet and stumble upon all of this information themselves. I do, however, recall a DP strategy guide I bought soon after the game was released that mentioned Effort Points, and gave examples on certain Pokemon who gave 1, 2, or 3 (surprisingly, they were correct despite the horrendous errors scattered throughout the book).
This article was a pleasant surprise when I went on the website a few days ago. I hope they continue to shed more light on how EVs / IVs work.