I am very much against the idea of forced diversity. I do not want to see "minority" characters shoved into a game, movie, TV show, book, whatever based on that single trait. It's a disservice to the work as a whole, a disservice to the audience and an even larger disservice to the people that character is meant to represent. I am a bisexual transwoman. I do not want to see poorly written or ham-handed depictions of what I am in any form of media. I would rather have no transgender characters than a shitload of terribly written ones. If the defining trait about a character is their minority aspect, that's a poorly written character shoehorned in for stupid diversity points.
If you want minority characters done well, Persona 4 has two shining examples: Kenji and Naoto. They are perfect examples of being a minority that make them both fantastic, well-written characters that are not forced. The Walking Dead by Telltale has excellent examples of "non-white" and "non-Asian" characters, and LA Noire uses race in an excellent way to color the world it presents.
Put simply, do what characters suit the world best, don't use token characters and do not force diversity for diversity's sake.