For a theoretical debut it looks decent. Not sure why all the hate. So Khrome was a badly molded action figure. And? That's like saying that hybrids and crippled beings don't have a right to live either. Let him be and see what comes out of it. MK is full of glitches. Just because Khrome is rather a mistake than a glitch, but that doesn't mean he can't be made into something worthy. Give him a story cameo and let's move on from there. If the response is good, make him DLC. If not, forget him. Easy.
As for his character bio, I'd create a story for him that would go something like this:
Khrome wasn't always the metal bending ninja he now is. In fact, not too long ago, he was still a mere mortal. Working for a mining company in South America, as taxing as his job was, he was able to secure himself and his family. But Esteban Fernandez, as he was then known, wanted more. He demanded appreciation and respect. Becoming obsessed with the minerals he drilled, he seeked the ultimate gem. Inside ancient caverns, remote from civilization, he found much more - a relic of unimaginable value. As he put it around his neck, the earth beneath him unexpectedly shattered. Falling multiple layers deep, Fernandez eventually reached the very bottom. Buried by walls of chrome, to his surprise still alive, the relic protected him from an otherwise certain death. That, however, came at a price. Being magical in nature, the talisman also gave him the ability to be one with the metal substance and control it with his will. An accident that changed Esteban's life for good and granted him everything he desired. From this day on, Fernandez was no more. There was only Khrome.