Very good image. My eye enjoys following the descent and the main body of water has an intriguing gesture that reminds me of one of Duchamp's Nudes (descending a staircase). Also like the subtle changes of colour in the water and the curves of the aurora-type veils.
If the scene had been more brightly lit, and shot using an ND filter, would it have changed anything about the look of the photo apart from the usual effects on the water? I'm going to be trying out ND filters soon and hadn't thought about any effect they might have on colours, tones etc until you mentioned that you hadn't used one in this shot.
Cheers,
Kate