It is adding in other people of colour and gender not because they would make an addition but more to prove how progressive and what not they are. Similar to quotas for hiring people, they're retarded.
So "white male" is the default and any deviation from that default must have a proper reason for doing so?
Read: We hired people who had no skills in the field we hired them for, but because they were not white, cis, male, or straight they were hired. "White male is the default." That is so fucking retarded. I am questioning my continued attempts at being nice in my argumentation.
Even if Overwatch sold great it has Pixaresque art design and that's popular and it comes from Blizzard which made StarCraft, Warcraft and Diablo. That's a ton of name recognition. Blizzard games also all get accessed through the same client meaning you load to play one game and the others are advertised. There's also cross promotion. Like do something in Hearthstone to get something in Heroes of the Storm or whatever. And Tracer isn't getting in our face telling us she's a tranny, people just joke that she is one. Overwatch characters basically just happen to be diverse. I don't think the killer robot enemies are supposed to represent white people or something.
TBH games set in the far future having black white and other people made up of modern defined "races" makes no sense to me... surely by then with the rate of globalisation the races would just fade away into some sort of middling semi brown race...