It's hard to say what we should give him credit for, since games typically have so many people credited with different parts. From what I understand, Sakaguchi and Nomura wrote the base story and concepts for FFVII, whereas Kitase and Nojima adapted that for the game you actually got to see on the screen. Even with interviews, I doubt we could really say who deserves the credit for what. I also think it's undeniable that the Xenogears script which was pitched as FFVII had a tremendous impact on the game that later assumed that title.

All I know is he wrote some of my favorite games ever. I know he gets a lot of criticism for some parts but that's almost always unfair. Every game has red herrings, plot holes, inconsistencies, and instances of bad writing. People only criticize the stories to legitimize what they've already decided they do and don't like.