I though that Ball was the surprise at RB. I think he showed "Hyde" power and was consistently taking mulitple tacklers forward on several plays. He also was pretty quick to the edge. I still have yet to be impressed with Dunn. Either way the position overall will be pretty solid next year.
Additionally the defense as a whole looked good. However, these spring games give more advantage to defense than offense in my opinion. You can just tell the offense isnt all on the same page quite yet, but it takes more time to get to that point.... much more than just 2 weeks. It is fairly easy for a defense to play cohesively with 2 weeks practicing and only playing in a base defense.