Okay, to give an idea of scale: The entire panel is 34" wide and 20" deep. The spinner and top-button 8-way are 14" (to center) from the bottom edge. It's a slight reach, but not too bad. I could move everything down a little. It's just that I've heard people say you don't want the controls too close to the bottom edge, because you want some wrist/arm support if you're sitting at the cab on a barstool. But it could probably come down a little.
And the angle of the buttons feels about right like it is, for both players. Like DougHillman said, your hands angle inwards. We tried having two of us stand there each pretending to hold a joystick and buttons, and our hands fell naturally and we were facing the screen square on.
I could move the controls out to the sides a little more like people suggested, but not too far. I want to use the joysticks for two-joystick games (Robotron, etc.), and if they got much further apart they wouldn't be too comfortable.
The reason I have the bit of extra width is, once again, for support when sitting on a barstool. The pic below shows the angle of the player's arms. I didn't want them going off the edge. But it looks like I could definitely bring the edges in a couple inches, if I round off all the corners (so your arms won't be resting on a corner).
And yes, the whole thing is deeper than it needs to be.
So I think I'll:
Pull everything down a little, and get rid of some of the depth.
Round off the corners.
Lose some of the width off the sides.