I do agree that the photograph is a bit dark. However, I feel that adds more to the charm. The mood of the landscape is more sedate or serene, as opposed to bright and sparkling. As a result, it makes the piece very relaxing to look at. The way you captured the reflection of the sky in the lake is beautiful as well. The unevenness gives it a surreal quality, and makes you feel as if you are either about to tip into a mirror, or are in a dream. It also creates an excellent balance between earth and sky. I would brighten the exposure, but otherwise I think it's lovely! Wonderful job!
Both critiques are partially right, in my opinion. I feel that the horizon should not be in the middle; although at the same time I don't believe that much in standardizing methods. I personally love this shot for my own reasons