It is working great for me, but YMMV. Proper threading should fix those problems. Using openCV in the CRIO would be very hard, as you would need to compile it for the CRIO to get that super fast C code. You should try both out and report back to us with some metrics, since I have nothing but my NI Vision code to speak for. Personally, I see no advantage to having the laptop on the robot, since the lag between the robot and the DS is negligible. Perhaps threshold on the CRIO, send the (much smaller) binary image to the laptop?
To address your earlier point about the legality of a laptop controller, all output to robot parts (motors, relays, etc) must come from the CRIO. You can send any signal you want to the crio, just not to anything else. Back in 2008 my team used current based speed controllers that were custom built circuit boards placed between the speed controller and the motor, and it was fun convincing the inspectors that they were legal
