Originally Posted by mashnut
The plane of the disc is important, but if that doesn't match the plane you're pulling through on you have issues. That most often happens when rolling your wrist as you throw. It causes wobble, decreases distance and can make for unpredictable flights if you're not in control of it. Sure, that torque is a small percentage of the total torque applied, but I think it's disingenuous to say it has almost no effect on the discs's flight.
Normal wrist roll does not cause noticeable wobble. You would have to really intentionally flick/twist your wrist hard to impart wobble that way. An unclean release caused by the disc hanging/sticking on your finger/s causes the visible wobble.
The problem with wrist roll as you correctly point out is the plane of the disc on release. Off-Axis Turn of your arm gets your wrist to roll.