In the video clip that started this group snit, I don't see much head tilt in the first place.
Head tilt is NOT a good thing. There are a whole host of reasons, some dealing with control, some with injury prevention. Still, lots of effective pitchers have it. You wouldn't want to teach it, any more than you would teach a young hitter to copy Julio Franco's stance or swing, but clearly some people are capable of having departures from standard form and still doing well.
One thing I would note is that head tilt often accompanies a dragging throwing arm. In fact, the dragging arm will result in the ball's being delivered off the plate to the arm side (to the left-handed batter's box for a lefty) unless either the drag is corrected or some other accommodation is made. Most kids start pulling their torso to the glove side, leading with their head, to compensate for the dragging arm.
The best cure is to get the arm up and out front sooner, so that the head is behind the hand. If you do this, the head will be more straight on to the plate. In other words, instead of solving one problem (arm drag) with another mistake (head pull), you're better served if you fix the original problem and eliminate the need to compensate.
Again, in the video, there is only a modest amount of arm drag going on, and thus, only a slight head pull. In this particular pitcher I don't see much cause for alarm, and if he has good arm health and is effective, why mess with success?