So is the blurry background just a placeholder, until you create a much higher resolution background? Compared to the hard edged city, that blurry background looks really bad. If you plan to eventually fix that blurry issue, then don't take this criticism too harshly. Its just the hardlined city and super soft background just doesn't sync well - looking at odds with each other. I'd both soften the city, and use harder edged elements to the groundscape to bring these two varying elements in line with each other. Just a suggestion.

GP