I love the grey background. It suits him so well, grey is the colour of his armour and his soul. He is not good nor evil, not black nor white. He is grey. In my opinion one of the deepest and most true characters in the series.
I don't think this is too pretty to be Sandor. His face really looks like his brother pressed it down into the fire, the scars and the missing ear. I also really like his facial expression, it's very true to what the monk said to Brienne about him in A Feast for Crows.
"Too pretty looking to be Sandor Clegane;" Frankly, I disagree. You fit the description of him fairly well, and actually took into account the fact that he has a pretty long face. The only think I disagree with is the way you drew his chin and his nose, but I always imagined his nose standing out a bit more than that. And I have a thing against cleft chins, no clue why. All in all, though, you did a wonderful job. Even the gap on his jaw is well proportioned.