Aw naw, they're going to show his origin? Why would they do that?
According to the New 52, Joker threw Harley into the same vat of chemicals that changed him, so it might be her origin.
That sounds more likely, actually. And Harley was the one who the Joker had strapped down in the trailer, so we already know that there's going to be some form of origin for her.
Also, on the notion of Wonder Woman:
http://www.thewrap.com/chris-pine-closes-deal-to-star-opposite-gal-gadot-in-wonder-woman-exclusive/Yes, yes, insert obligatory joke about how they beat Marvel to casting another guy named Chris here, etc. Anyway, this part made me raise an eyebrow:
Steve Trevor will be no mere love interest for Gadot’s Diana Prince, as there will be plenty of action to keep him busy
Ideally, no character should be a "mere love interest," but I'll be very disappointed if this means that they're going to be bending over backwards to avoid implying that Steve is anything less than Wonder Woman's equal in ass-kicking ability and importance to the story. God forbid, the idea of a relationship where the man is content to take a largely passive, supporting role and the woman is the one who gets shit done.