Mine actually arrived yesterday from DeepDiscount, a full day before it hit store shelves, even though I chose DD's free shipping option, which usually takes longer. Anyway, haven't had a chance to watch much of it yet, but I can comment on a few things. I posted a brief comment on the New Frontiers promo yesterday in the "Favorite Episode of Season 4 of The Batman" thread, so I'll just copy and paste that here, and then I'll add a bit about the "The Batman Season 4 Unmasked" feature, since Ruseri asked me specifically about that one:
NIFTY 3 minute 40 second promo for New Frontiers on disc two (featuring Bruce Timm, producer, for one!). I'm really looking forward to that DTV. ... Oh and Lucy Lawless (also seen in the promo, throwing herself into her voice acting with full motion) is a blond now.
"The Batman Season 4 Unmasked" (9 minutes, 21 seconds) featured commentary from the people you'd expect:
-- Alan Burnett
-- Jeff Matsuda
-- Andrea Romano
-- Michael Jelenic
-- Rino Romano
-- Michael Goguen
-- Paul Dini
Interestingly enough, no one addressed the change in animation elements (Batman's new chin and nose) at all.
Jeff Matsuda talked about the move for Season 4 toward more "event style" stories. He said the very conscious goal of everyone involved was to make Season 4 The Batman's best, and to really please everyone's "inner geek."
Andrea Romano commented on how impressed she was with the evolution of the story telling when she read the scripts pre-season.
Matsuda admitted that perhaps early seasons had been too Joker- and Penguin-centric, and said that there was very conscious effort to expand the Rogues Gallery, and to make the Joker and Penguin appearances that they did have count. He said that the decision of whether to use a classic Batman villain or to invent a new one was purely story driven: If the story called for elements that didn't fit well with existing villains, then they did create a new one; but if, for example, they wanted to test Batman's mind, then Riddler was probably the choice.
In relation to that expansion of the villains on the show, some time was spent talking about Harley, and about the fact that having Dini write that story was a natural, since he invented the character. The comment was made that, in contrast to Timm-verse Harley, this Harley was never really the Joker's "henchgirl." She and the Joker "went out on the town" and then cooperated, on her goals, so that she was more of a "peer and ally" and less of a "yes, Mr. J" girl.
A number of people commented on the progression of Batman opening to ever-larger cooperative teamups -- moving from the loner of early seasons, to the teamup with Batgirl in Season 3, to the partnership with Robin, and then all three, and finally to Martian Manhunter and the JL. It was about Batman moving from being merely Gotham's superhero to being a superhero of "the world, and even the galaxy." It was acknowledged that the reason Robin was held out of the show until Season 4 was his presence on Teen Titans.
Alan Burnett said that The Batman Season 4 was one of his favorite seasons from any show he's ever worked on.