According to the director and scriptwriter behind the original core entries in the Pheonix Wright franchise, Shu Takumi, the series would have ended after the third game if it was up to him. During an interview with Official Nintendo Magazine, Takumi stated that he felt “Phoenix’s story had been told, and that the series should not continue.”
“Knowing when to end a story is very important and I wanted to avoid dragging it out and having it become a shadow of its former self.”
That doesn’t mean Takumi completely had to swallow his pride just to let the series continue, because Gyakuten Saiban 3, AKA Phoenix Wright: Ace Attorney – Trials and Tribulations did allow him to wrap up Pheonix Wright’s story and the series only continued by introducing a new lead character.
“Years later, when it was decided within Capcom that Ace Attorney 4 would go ahead, my position was that we should change the main character and tell a new story. I didn’t plan to have Phoenix in the game, but my colleagues said they wanted him to appear in some form, which is why he ended up being the accused in the first case in Apollo Justice: Ace Attorney.”