Maybe its just the lenght of the weapon part. i guess it could look ok If you could end the weapon right after the "big" prism.
And while I'm being a bit of a D-bag, I guess I can point out that I don't like the Night Spinner at all.
To me, the turret looks way to bulky. I think the Falcon/Serpent/Prism body looks so cool and sleek, and then they F it up with these bulky, ungainly turrets on them and just (in my opinion) destroy the speedy look of the model.
It just kinda blows to see what should be a really cool model look bad.