As previously announced/leaked, AA6 takes place in a foreign country which Phoenix visits "for a certain goal."It also mentions that the people in this country have some sort of belief in the spirits of the dead. While there, the old Wright luck kicks in and he finds himself wrapped up in a certain case when his tour guide is arrested.
Phoenix goes to see the trial, but when he sees there's no defense attorney and the judge is relying on things like an "oracle of spirits" (insert your own Zelda joke here) to hand down a guilty verdict immediately, Phoenix objects and takes the defense's bench.
Character-wise, that tour guide's name is Bokuto Tsuani (boku to tsua- ni -> "On a tour with me"), a young energetic monk-in-training. Once he gets on the topic of tours, he can't stop, but that's not much use for him in the trial.
Also appearing is the mysterious, strong-willed woman in the art above; the magazine states she is neither a witness nor a prosecutor nor a judge, but rather a "fourth role" in the courtroom and this game's "key person", like Athena in AA5. (To be very clear: it does not say she's Phoenix's assistant, just reuses the "key person" term.)
As for trials themselves, as previously shown, the courtroom has a large “water mirror” which plays a part in a new system they’re keeping under wraps. The magazine also seems to suggest there may be other small changes from the usual courtroom antics. This new system will be playable at TGS 2015.
What's more, during the interview Yamazaki
explains that in this country, there are prosecutors, but no defense attorneys - defendants must use a "certain object" to defend themselves.
In the interview, the developers discuss how the game's theme is a "courtroom revolution" and how they felt Phoenix was in a position where he didn't really have anyone who could match up to him in Japan, so that was part of the reason they moved him into the wider world.
They also hope that trials in a court where the usual "rules" don't play will help give a sense of urgency to the game that they couldn't get in just a plain Japanese trial.
With regards to the game overall, the developers heard a lot of complaints that AA5 was too easy due to the many hints characters gave, so they're aiming to let the player enable/disable hints on their own, and to avoid direct clues like in AA5. And while development's still fairly early on, they hope to make a game to surpass the previous entries, and to "betray the player's expectations - in a good way!"