Wow, I didn't even notice the guys in there- cool tank! I do think it looks a little small/under armored for a tank but that's just me. I think maybe some more tiles or plates would give it more of an armored feel. Then again- I'm also a couple months late to comment on this so someone's probably said that. :)
Quoting Keith Goldman
General this model is currently DQ'd, however nice it may be, it uses tracks. "4. Your Armor MOC must use either wheels, hover-fans or anti-grav. No tracks."
Keith, while it is true that what LEGO uses for track pieces are used, they are used to build wheels. The vehicle is a three-wheeled design, and the track pieces were simply an appropriate piece for customizing the size of the wheels and making them look less cheesy than one-piece rubber wheels. An instance of "NPU" if you will.