I noticed that the image has a scanlines/grain, and I'm assuming you added those, right? :P. I think this image is simple, but perhaps lacks a little bit of strength. My suggestion would be to perhaps use a higher contrast background in comparison to the character of Kumo. If you put him against a darker backdrop, then the image of him will pop more and have a stronger impact.
I'm guessing you probably wanted to maintain the idea of clouds, and that etheral feal by using such a backgrounds, but a little bit more contrast could still be used to improve things while maintaining that feel. I think the composition is good, and so it's just the colors that could be improved.
I actually liked the anime more than many other people I know, and ended up buying the whole thing. I know that it didn't quite live up to the FF standard, but it was still a good show with many good designs.