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