Well here are some things mentioned from the article.
1. At the time of development of "version 1" the Hot Toys team didn't have a lot of material to work with. After seeing the movie Yulli and JC Hong saw room for improvement especially with the Joker's expression and posture. So when plans for the "Bank Robbery" Joker were brought up they decided to redo the sculpt. As a matter of fact they went for two expressions to better represent the Joker. This "serious" approach to present the Joker seems to contradict the Joker's very own "why so serious?" line, but it is to the benefit of collectors.
2. Release date in November (delays are normal with Hot Toys though so don't be surprised if it is bumped to December).
3. The neck post is done in a way so that the Joker's hunch can be accomplished.