I remain confused BY those confused about the diversity on Titan.
Certainly as we were writing the first three books (Mike, Christopher, and I), the point that one of the main purposes of the ship was to have as diverse a crew as Starfleet had ever had on a ship, was predominant. It's there in the plotting, it's there in the scenes, it's there in the dialogue. It's even there in the ship's motto. Complaining that Titan is "too diverse" is like complaining that tomato sauce is "too tomato-like."
Which brings me to my next point. Any author (or screenwriter) who writes a future in which everybody gets along beautifully, all is copacetic, nobody has conflicts except the enemy, every element of diversity is homogenized, nobody has "special needs"... that's pure feldercarb.
Distilling it down: I go to a monthly potluck of like-minded gay guys, many of whom have been friends or colleagues for a decade or two. We're all there for two purposes: camaraderie and food. Does that mean that we all get along beautifully all the time? Does that mean we eat all the same food? I have dietary restrictions against peppers. Somebody else is deathly allergic to walnuts. We have some people who are robust and super-healthy, and some aging attendees whose health is failing. Provisions are made for health issues, for newcomers, for the super social, for the less social, for moods, for all sorts of things.
That potluck is not unlike what I imagine a starship should be like (or a productive group or society of any size). People joining together for a common purpose and finding ways to make it happen (except in the Federation's case, you have the added element of military and scientific training aiding those goals - and on a starship you have added command structure).
So when I write a Federation ship, I ask myself: Why should every humanoid be white and Judeo-Christian and American/Upper European? Why should a ship have only bipedal humanoids? Why should everyone get along all the time without conflict?
Homogenization is NOT perfection; it's the eradication of differences. There are those who want everyone to look alike, think alike, act alike... be a Master Race.
Acceptance and embracing of diversity is much closer to perfection. To understand that sentient beings do NOT look alike, think alike, act alike... that is both a HOPEFUL approach and a wellspring for a writer.
This probably has rambled for a bit (I'm hungry and dinner is calling), but hopefully some of the points are understood.
[And I fully appreciate those who do get a bit overwhelmed by all the characters in Titan. We had many discussions about putting a Dramatis Personae in each book; I was 500% in favor of it, but not everyone was. And I wish that we could get a Titan comic going so people got to see what everybody was like. I think either a DramPers and/or a comic would get everyone over the hurdle.]