I think Malenko is referring to the shape of the CP. He's not a fan of the aircraft carrier design.
His carpal tunnel comment is due to the extreme downward slant of the CP. You might want to straighten it up a little.
You got it! But the kid grabbing the joysticks comment is more about the center mass of the cab. I don't think they'll be much unsprung weight to the cab so it will be very prone to tipping unless hes going to fill the bottom with sandbags or weights. The angle of the CP just adds to the problem. Here's my CP for my old 4 player MAME cab, exact same dimensions as NBA Jam/Open Ice/ NFL Blitz (ya know, actual 4 player games)
Changes made:
aligned the sticks so that smash TV, Karate Champ, Robotron, etc could be played on each set of sticks
adjusted the button positions for player 4 a little bit
added more buttons to the center players
had a button UNDER the CP, wired to ESC