Back in the day, FFII and FFIII both got novelizations by Kenji Terada, one of the head writers at Square. When they released the DS version of FFIV and the The After Years Cell phone titles, both games received novelizations as well, though they are pretty similar to the game's format from what I've heard.

Not to mention the novels that accompanied Advent Children, FFXIII, and the manga adaption of FFXII. So it's not really anything new.