Personally, I thought JZ was dominating Aoki up until the elbow on Shinya's neck. Shinya Aoki is just too one-dimensional and I'd still pick JZ to beat him when they fight next.
Dida looked like crap against a very impressive Alvarez. Dida's supposed to have an improved ground game, but it really didn't show. His striking didn't look all that impressive either, very loopy punches, which at times were simply being throw from too far outside the pocket.
I haven't got time to watch the other fight videos today, and I know most of them went to decisions, but I'd say out of what I watched, JZ or Kawajiri is going to win this tournament.