Well people associate Nomura with a certain style of characters (i.e mopey emos who look like they want to be fashion models) and a certain type of storytelling and themes (overly melodramatic, slightly self-absorbed, eager to appear deep and philosophical).

Whether he actually deserves that or not, I think it's quite hard to know from outside of the company, because you never really know how much of the final product each developer is responsible for.

I would say though, the 2 main games in the core franchise that he had almost no role in, FF9 and FF12, are quite notable in how they don't exhibit any of those characteristics I described. So it might be true that he's responsible for that aspect of the series.