I really liked the two windows formed in the rocks on the side of a hill in Cappadocia. What I really liked was the golden light of the sun as it set, it really illuminated the insides of the rocks, and the polarizer really helped bring that out. I would have liked a perspective more to the left, but I would have tumbled to my death so I decided against it :)
Sony A700, Sony 16-50/2.8SSM@50mm, ISO 200, F/9, Polarizer, handheld, 2013 Cappadocia, Turkey (wish I had a longer lens to maybe isolate the windows more)
I think this image would have more appeal to me if the 'windows' were completely visable for the full circle. I agree with Colin that a darker foreground might focus the eye a little more on the windows, along with your self critique of longer glass for better isolation.
A nice play of light you captured here - I agree that it's just not there...couldn't you crop closer at least as an alternative for not being able to change the perspective?
Tonal contrast looks good and natural.