Nah, looks fine to me. You dont need airflow over every part of the heatsink, the idea of a heatsink is that its good at transferring heat. 6 of those 120mm ? fans should be enough to get rid of 800W.

edit:
Well, Im not sure if the two outer heatsinks get a lot of airflow or if they are connected to the "inside" heatsinks on the same bank.

Still, more worried about this being real. If it is, I wouldnt mind modding it.