From my experience, it has been beneficial to have a programmer as one of the drivers. For the past two years, we have had the lead mechanical student as the driver and the lead programming as the operator. Since we have used simple skid steering for the past four years, sometimes with shifting, the method of driving around the robot has stayed relatively the same. As for the mechanism, it is much more game specific. Because it is new every year, the method of controlling it will drastically change with the game.
I actually prefer to have a programmer on the drive team. Though he might not have quite the same grasp of mechanical limitations as the mechanics guy, he knows exactly how it is supposed to move. He has made any code changes and configured all the controls, so he will already know any basic controls or manual overrides. He can make any tweaks he sees.
As well, it's nice to have the ability to trace down and fix nearly any problem on the robot between our driver and our operator. Our "pilots" know what they are doing.
If coding needs to be done on the fly, we can just bring the laptop to queue with us.
But, since I am the programmer, I am highly biased.
