For some reason the preview is horribly blurry. That´s definitely not the case :D.
Examine your original image at 100-300% magnification. That's when imperfections become more noticeable.
The exposure levels are uneven.
And the white balance is not neutral (too cool).
Hope that helps.
Love the color and symmetry, but it looks a bit dull and muted; with just a few minor tweaks in LightRoom it looks much crisper. Increase exposure slightly, raise the shadows a bit, set the white and black points, and apply a bit of dehaze. I assume you have a Property Release? Otherwise, even if you overcome the technical issues, it will be rejected based on IP violation.