Great capture. I only find a little too flat. Have you considered adjusting a bit brightness and contrast
Al

Your photo is a very effective one as it is. I would have made it exactly the same way. I also like mod 1 (Martin) and 3 (Willie).

If I am 'forced' to find something to modify, I would only tilt it by 1,0 degree to the left
Great work indeed

Nice idea. I think that a tighter crop (to eliminate the overexposed part of the bag) and a better control of the exposition on the subject could make it a much better picture. My personal opinion
Al

My opinion is the following:

1. Yes the picture is too dark. You should increase brightness and contrast (eventually working also a bit with dodge and burn tools to increase depth)
2. the background is too visible and distracts too much the attention from the main subject. You should apply a blur filter and/or darken it
3. The frame and signature are too heavy and do not add anything to the image. I would eliminate the first one and reduce the opacity of the signature.
4. a little more background space in the upper part of the image could be nice (if possible)

Hope this can be of some help
Al

Nice capture. I like the composition very much. I would have loved to see more details on clothes and hair. Maybe with a little dodge and burn? Just my idea
Al