Ugh... lemme clear things up. Phoenix Wright Ace Attorney Justice for all is the english version of Gyakuten Saiban 2! Which it's coming out in JAPAN FIRST as a remake with the english version we'll be getting(same exact english translation we'll be getting... WORD FOR FREAKIN' WORD!). Also coming out in Japan this year is Gyakuten Saiban 4, which is the first NEW Gyakuten Saiban game to come out in Japan since the 3rd one for the GBA. This new game being released does NOT feature Phoenix Wright as the attorney you play, but instead a new attorney who also happens to have an odd hairstyle.
So in a nutshell, Gyakuten Saiban 2 = Phoenix Wright Ace Attornet Justice for All, both have the same english text, but the Japanese version is being released first. Gyakuten Saiban 4 = JAPAN EXCLUSIVE... for the time being. Whether or not the title will contain english text is not determined yet, but odds are it won't. Also, it's been built from the ground up for the DS so it should be using more of the DS' special features.