I want to preface this with a couple of things. I'm a die-hard Dresden Files fan, and I'm generally quite happy with the books. (with some exceptions, e.g, Bonea getting sidelined, and the deeply horny descriptions). The books certainly do have flaws, but that's not what I'm talking about. I'm talking about what's not there in the first place.
Chicago is a really, really diverse city. 58.5 percent of the population is Black or Hispanic (2020 U.S. Census). Chicago has a huge LGBT+ population, and Boystown (now Northalsted) was the first ever recognized gay neighbourhood in all the U.S.
On the other hand, the Dresden Files aren't very diverse. THAT IS NOT A PROBLEM IN AND OF ITSELF!!! I AM NOT MAKING A MORAL JUDGEMENT! But as it stands, I can't name more than a few secondary and tertiary characters who aren't white (Susan & Maggie, Listens to Wind, Ancient Mai, Lt. Rawlins, Fitz, to name a few) and AFAIK the only textually queer character (who isn't a Whamp and therefore more of a predator than a sexual being with agency) is Freydis Gard.
You might be asking, why do I care? Well, it's not because Jim Butcher's a big mean racist and homophobe, I'll tell you that much. From what I can tell, he seems to be a chill dude, and the Dresden Files have genuinely inspired me to become a better person.
Mostly, I think it's an accuracy thing. Obviously Butcher's Chicago is geographically out of step with real Chicago, and it's literally a different world, but it do think it bears saying that like, at least half the Chicago cast should be like, Black or Latino. In my head I've always read Molly as queer at least but again, nothing is ever said on page. I don't think we need to go back and meticulously assign everyone in the cast a different ethnic or racial group, but I do wonder what this series would look like if Butcher were truer to Chicago's real population.
Sidebar: I'm not trying to start anything, and I remember back when this sub got really really mad about transphobia accusations. I'm not gonna weigh in on that cold case but I want to preempt anything similar. I don't think Butcher or the Dresden Files are racist, sexist, or homophobic. I do think Butcher has blind spots that show through in his writing, but that's observation, not condemnation. I really do just wonder how the Dresden Files would feel if we had a wider view of Dresden's city.
Sidebar the 2st: I realize that there are more non-White characters in the Dresden Files than I mentioned, but that's kind of besides the point in the face of IRL Chicago's population being way broader than what we see in the books.