As someone who has the original Ao no Exorcist anime in his favorite list, I find the sequel disappointing.
First, the Story (3/10):
The sequel begins after half of the first season and it's confusing to follow and you wouldn't know what the hell was happening. The sequel's environment is a serious compared to the original. The story failed to grab my attention and I found no reason to continue watching except that I am a fan of the original series. The action scenes were bad and quite few.
Second, Art (9/10):
The art style in this season is a big improvement compared to the original. The backgrounds are
beautifully done and they are all magnificent. However, I find the characters' art style was less quality. Most of the characters' art style was averagely good but they didn't fit the beautiful background, and a few were bad and didn't fit at all but I am happy with the improvement.
Third, Sound (8/10):
The sound was good but forgettable. The OP was great if I may say so.
Finally, Enjoyment & Overall (6/10):
This sequel was disappointing and I didn't enjoy it very much but I have a feeling that the unannounced sequel is gonna make up for it, so I will be waiting for the sequel patiently.