I've used this analogy before. Who makes the best hitting coach in baseball, a natural hitter or a player that is a moderate hitter but has had to work at it every day of his life?
The natural has always had the ability to hit. He will look at a player and say, "Just wait for the ball, when it's a good pitch, swing." Because of his ability, he's never had to really take apart his swing and relearn it.
On the other hand, the moderate hitter has analyzed every step of the process of hitting a ball, stance, swing, follow through. He may never hit the ball as well as a natural, however, he probably knows the process better than most people. Most likely he can do a swing analysis and talk another player through the process of learning to hit.
The same thing is true in skiing. The key to a good coach is knowing your subject and being able to communicate effectively with your student. You don't have to be a great skier to be a good coach. A good coach wants his students to surpass him and will help them do it.
As far as being able to do the movements, again it depends on the coach. I've had great paraplegic coaches sitting in monoskis teach me how to move properly to improve my stand up skiing. You don't have to be able to do the move, you have to know what the move is and how to coach someone to get there. (I've also watched poor coaches that didn't understand the moves screw up students. But that's a whole other thread.)
A good coach/mentor will critique a student and provide positive feedback. They will not be a vicious critic who does not provide ideas or solutions for problems.
Now I will admit that most professional athletes will understand the moves of their particular sport in fairly good detail. However, when it comes to a coach, I want someone that not only understands the moves, but also has the love, desire, and passion to coach effectively. A good coach knows that it is not about the coach, its about the student and what the student is getting out of the teaching/coaching effort. (Done right, the good stuff has a way of coming back to the coach, but thats a side effect of good coaching, not the primary goal.)
So, I think the proper statement should be;
|A student needs a coach/mentor rather than a critic.