Thanks for this opportunity Pom. I know I have come in a bit lat on this one, but here are my thoughts.
Dawn 1 seems really unbalanced to me with the crop you have chosen. I feel a bit skewed, I think because of the angle of the line of main ice.
Dawn 2 just doesn't work for me and the image feels really cramped. It feels like the image has been cropped.
I actually prefer the composition of Dawn 3 - your original - because the curved line on the left has not been removed, which I think contributes to the expanse and depth of the image. When it is cropped out, the image seems severed somewhat. I personally feel that cropping off the right hand side rather than the left (to remove the bit of ice) works better, to create a more fluid "S" to lead the eye across and to the back of the image. I have included it here just to illustrate my thoughts.
I also agree that some cleaning up of the water may not go astray, but am not competant enough to do that.
Yes agree that I prefer your last image. It has a much crisper, cleaner feel, which is juxtaposed with the ruggedness and power suggested by the darkness in the ice. It has a similar diagonal element which I was referring to before, a"Z" this time, which leads the eye through the three distinct distance focal areas- close foreground, middle, and distant horizon.
Pom, you mentioned becoming frustrated with photographing some of Iceland because of the overwhelming nature of the geography. What about some really zoomed in shots, rather that the landscape cliches which you mentioned you were trying to avoid? I can see some amazing images with the colour and shapes of the ice and terrain, without having to encompass the whole panorama. I would suggest having a go at going further into 'extracting a landscape from the landscape', by zooming in much more closely.
Just an example of what I mean compositionally from the image you provided, of course it is destroyed by the resultant resolution, but just enough to get the idea. I would zoom even closer than this example even, and still create the feeling of expansiveness by including areas of plain water/reflection/ice.
When is your next visit?