There is a time for breaking the 'rules' and I think your photo is one of those times. Yeah, the thumb is a bit on the bothersome side but certainly not deal breaker. I think the pose and overall set up are simply excellent. The tones and colors, background, flooring, chair and model, including her hair work together beautifully. The way I see your photo is that it's about attitude, or rather "attitude!". As someone else mentioned, I could easily see myself hanging that one on my wall! Dark eyes? Yeah they are, but that just adds to the "attitude". I think that if the facial shadows were softned or the eyes were not shadowed, it would kill the image. A softer face would kill the attitude which make the image work. I love it as is!