This wall needs a lot of work.
I like the color scheme. I'm usually not a fan of warm colors, but this one looks nice.
On the other hand, the background, as you said, is random, and it doesn't work for me. Random backgrounds don't have enough aesthetic thought behind them. When you see abstract backgrounds that work, it's because someone thought about it. It's not just random.
Next the vector. The vector is decent. I don't think Haruhi fits in the whole idea, and Nana definitely would have been a better one, especially with how bold she is. I know Haruhi plays the guitar and sings in the series, but it still just doesn't fit her. The whole bold hard rock scene, that is.
Also, as mentioned above, Haruhi has a man-chest. Meaning her breasts are not drawn properly. Unless she had crooked small implants. Also, one arm is way thicker than the other. I think the idea was great, but the execution and final think-through fell short.

On a side note, it figures that a bunch of silly males would comment about wanting an uncensored version. I saw that coming form a mile away.