Mister Terrific the character had a much better chance at a solo than Cyborg, but the writer (who happens to be Black) could not stop focusing on his race and could not for the life of him write a good story. And the art was shotty. That's why Mr. T failed-not because he was good looking. You didn't disprove anything with your example.
It would be more difficult for Cyborg to have a civilian life, which makes him more difficult to relate to--that's a barrier for any writer. The most popular characters are the ones people graft themselves onto or the characters people want to be (Spider-Man, Superman, Batman, Green Lantern). Who wants to be a guy with a half-face?
Finally, if you look at the sales numbers for teen titans action figures when the cartoon came out, the Cyborg figure sold the least--by a lot. I worked at a target, and you couldn't give his toys away. Little kids care more about looks than you give them credit for (Eww, Rachel is fat. Bobby is the booger boy).
Finally, saying that talking about race is what keeps racism alive is the dumbest thing. From the time we are young we can see the physical and cultural distinctions among people. Humans also try to simplify things to make them better to understand--if he did this, then this other person must be similar for so and so reason. The best way to tackle racism--which is still institutionalized in our society--as any sociologist would tell you--is to talk and educate people about it.
We must have been reading different Mister T books because I don't feel the comic was at all focused on his race, but maybe I wasn't engaged in the story enough.
Do you have the link to prove your point on the action figures? Likewise there are other popular characters who are disfigured and monstrous, like Cable (half machine face), Deadpool, and (correct me if I am wrong here) Spawn. It just seems silly to me to say that a character can't be successful because he doesn't have a normal face.
But neither of those points detract from the discussion on this thread that the portrayal of Cyborg is racist because it denotes him as an African American who is less than human, which is a hypothesis that I disagree with and reject.