The quality of his music has been waning for years now, so it's good he decided to leave. Some people overstay their welcome, and I felt NU did that. He was obviously a great talent, but I could never really find the inspiration in his music like it was 10 years ago.
I always figured he'd stay on board with the main-stream FF projects like FFXII but this really sucks. His music was an inspiration to so many , and I seriously think it's his music that gave final fantasy games the touch needed to set it above the rest . That's especially true for the games before the age of flashy cinematics and what not. As for the comment above , seriously even if you somehow find the later soundtracks of FF VII-X to be sub-par , you can't honestly tell me they still don't beat the hell out of the soundtrack from FFX-2 which I thought was a disaster and FFXI which is mediocre at best. NU is a god amongst mortals compared to these new artists no matter what of his work you're comparing. I think SE is in trouble if they don't find better talent to replace him.