The skybox is pretty cheeseball ATM. I'm using D3D rather than opengl, but i'll fix the problem as soon as I get to it.
Also, I like your controller suggestions. The only problem is that sometimes you need to run the treads in opposite directions. In other words, it's necessary to sometimes have the left tread in reverse, and the right tread going forward. It helps the tank make tigher turns, and can even turn on a dime. I've got all this working... but to do it, I'll have to eat up both analog sticks for control. Still open to other control schemes though.
We may just allow you to switch the tank's "mode"... so you can focus the entire controller on driving, or targeting. But in the event of driving, you can still target and fire, just not as easily (D-pad perhaps). I kinda like the idea of it being harder to shoot while you're driving, but if you park your tank, you can get better control over your turret and targeting. I'm also thinking of incorporating modern laser targeting like what's used in the M1A2. When a tank is bouncing over terrain, it can still maintain a decent lock. But if it's too easy to kill this way, this feature will be removed or purpose made a bit crappier than the real thing.