With me, at least is basically on the following information
-Compositional Detail: Centered items often detract me from a banner, wether text, or images
-Following the points of emphasis: There's 4 areas where, if something visualy has appeal in the areas, then it becomes more interesting- Example being my Icon. Face, Fatted part of wing, Lower hand, Shoulde, the most highly emphasized parts sit around the middle on Diagonals. You want people to be able to look around the piece and find themselves always looking back
you're at least somewhat talking about the rule of thirds, right?
http://en.wikipedia.org/wiki/Rule_of_thirdslike, when watching TV, a person will always be to one side of the screen - never in the middle. a horizon will cut across the top third or the bottom third of a painting or photograph - never the middle. etc.
to apply this to your avatar, the wing cuts across the top third of the image. her body - especially the lines of her body that your eyes follow - is on the right third of the image. it is important to consider this in art.
your avatar is awesome btw.