By blocking, you PREVENT the enemy from getting any AP himself. Good enough, no?
Have you played the Beta ? its about getting AP yourself. in only 3 minutes is every second you block a wasted on.
Its all attacking.
I've been playing the beta, and it feels to me in my experience that it's just as important to prevent the enemy from getting AP as it is to get my own, so *block to stop their attack then follow through with my own juggle*, that kind of thing, seems alright to me