There is a vastness of nature here in terms of all the elements. Maybe this is lost if the sky is cropped. For me the expanse of sky is needed to complete the dilemma of: Is this a shaft of brilliant sunlight or is it brilliant moonlight?
Talk about potential! Dave's comments really hit home with me. The expansive sky may be impressive, but cropping some off I think would balance the image better compositionally. The contrast between the shimmering water and the silhouette is very appealing.