I couldn't help but find it a little amusing that the article's author said it was offensive to him as a person of color that "Bioware thinks black people will call them racist if they don't make a world with us in it". There are lots of different people who I think have leveled that very accusation at Bioware for that very reason. I think that highlights the problem of trying to speak for or be outraged on behalf of an entire group of people in situations like this.
And also yeah he is wrong about the history of non white people in Thedas. Rivain was always a place where dark skinned people came from and it also isn't shoehorning all peoples of color into a single nation. There are some Antivans that appear to be dark skinned. And it's a different dark skin than Rivani.
Rivaini skin appears to be black. Antivans appear to be Latino.
I was kinda of two minds when it came to all the new racial diversity. On the one hand, it was good that there are clear examples of different types of people, but there didn't seem to be any rhyme or reason to it. I love Ser Barris, but he's the son of a Ferelden noble with a skin tone that is similar to Vivienne, the daughter of merchants from Dairsmuid. To me it kind of diminishes the diversity of the world if every nation and every tribe in Thedas all have equal numbers of all people.
As far as the darkness goes. I don't know. I thought all three games were fine as far as that goes. I've heard jokes making fun of Origins claims to being dark even when it first came out. I guess I can see where he was coming from in some caes, but I didn't feel something fundamental vital to the tone of the franchise was missing. I did notice a lot of horrible things seemed to be mostly in little easter egg bits of content you have to explore and read a codex for, and then don't deal with.