First off, thanks for all the kind words guys, this pic took me a while to complete so its encouraging when people take an interest. The city is completely fictional and not meant to represent any real life city but I think its cool that you guys see elements of real cities in it.
Now to get to the critiques:
@kuze - I totally agree with you, the city could definitely use another neon sign or two to make it come alive/seem busier.
@ElectricGrave and oliverclaude - Yup, admittedly I did not leave enough room for the fighters to actually battle, the only way it would work with the current pic is if we cut off the fighters feet and bring them closer to the camera otherwise it would seem "off". I'll have to extend the pic down a bit to remedy that. Also, its true that the rooftop does seem simplistic and unfinished compared to the rest of the pic but I was concerned that if I gave it detail it would further clutter up the pic and then the rooftop/arena would not be easily discernible, so I chose to make it bare. I should definitely fix it though, so thanks for the keen eyesight guys.