http://xbox360.ign.com/articles/621/621163p1.html

Finally, it wouldn't be an Itagaki interview without comments on other developers. Rather than speaking about specific developers, Itagaki states that the entire Japanese game development community seems to be unhealthy based on their showing at E3. He asks, "At a time when such an awesome machine is appearing, why aren't you trying harder? Aren't you the software makers that represent Japan?".
Itagaki seems to be drumming up 360 support as he adds, "I was hoping to see what kind of beautiful scenes you could make for the world's most powerful game machine, but there was absolutely nothing. There are probably some developers who read this and say 'What's this fool talking about?'. In that case, you should bring forward something more exceptional than what I've made."
Moving on to the three new characters featured in the game, Itagaki first talks about the character that he refers to as "the mysterious masked wrestler." There are two things that we apparently should have picked up from the trailer: one, this girl is Tina's friend, and two, she's not a standard professional wrestler. Her fighting style is based on Mexico's Lucha Libre style of wrestling (also featured in games such as King of Fighters, whose Ramon makes use of the style). Team Ninja made use of pro wrestlers to create the girl's motions.
A second new character, Kokoro-chan, whom Itagaki confirms as being Japanese, makes use of the Hakkyokuken fighting style. This is a style associated with Virtua Fighter, which Itagaki mentions as being the origin of 3D fighters. Team Ninja is apparently working hard to top Virtua Fighter's presentation of the style, which Itagaki praises as being "cool."
On the note of characters, Itagaki reveals that the "main" character for DOA4 is Helena. In fact, she wasn't shown in the first trailer because Team Ninja wants to give her a debut worthy of her new status. Going along with Helena's new central role, the DOATEC storyline will serve as the center of DOA4's story, with Itagaki pointing out that the Tri Tower DOATEC base has been created (and shown in real time in the trailer) for DOA4.
In all, Team Ninja is aiming to have more than 20 characters in DOA4. The characters will all have interconnecting storylines.