AJ Cann is actually their highest rated OL commitment...he's the #2 center in the country. But you're right, they are taking a lot. I don't know I've seen that many in one class.
But looking back, they only took 5 in the last two years, and none of them were very highly rated at the time (don't know how they've turned out, but if I had to guess, I would say not that well). Also, you never know if a couple of them could end up on the D-line. Our Nick Fairley was recruited as an offensive lineman coming out of HS. He was a 255 lb lineman in 2007....now he's a 295+ lb tackle.