These three are mostly minor suggestions and as such I'm clumping them into one post instead of making them all separate. Please judge them independently.
Improved icons
It would be very helpful if the engines denoted if they were for clockwise turn, counter-clockwise turn or thrust. Doesn't really need much more than an curved arrow on the previous two. A denotion on which gun is breaking down would be helpful too, as you're generally only concerned about 30% of them in a close fire fight.
Finally it would be nice if fire wouldn't completely mask the icon of what is burning. A single second can often be the difference between an extinguisher and a wrench.
Joystick/mouse steering
Simple to implement really. If left-right is bound to an axis, let the offset amount dictate the pulse frequency. Further away from center = Faster pulse. Would mean it would be possible to make slow turns without playing GOIO: The game of rhythm.
Engineer name
Look. We all know both TF2 and Return to Castle Wolfenstein had engineers. Despite this an engineer isn't someone that quickly fixes stuff by hammering at them. That's a mechanic. I know it's really minor, but it's like calling a construction worker an architect.