TLDR: Worth one watch through
I think it's an okay movie. The diverse cast and a primary character that is homosexual does not affect the plot at all. So if that's your beef with it. Move along.
I think how the story progresses is often forced and characters change their opinions on a dime, which is not a very human trait. The plot itself is interesting, but I don't think they took a long time to hash out how the plot should unfold. So while the overall story is good, the journey to the end is not as enjoyable as it could be.
The big let down is that Pixar normally has excellent jokes sprinkled throughout their movies, but this one failed to deliver on that and is likely the reason I will probably not watch this movie a second time.