When the Sedins struggled in their 1st couple of seasons as Canucks, Messier told them to just try to play their best in the way they are capable of playing, in another words playing to their strength and since then they had been steadily improving and eventually become stars in this league in their prime.
I think with skilled players you can't constrain their development too much by telling them to change their games entirely. They have been successful because they can do X. The things they can control is being more discipline like not taking bad penalties and standing around not checking other players or make too many blind or weak passes. The defensive side of games takes time to develop, especially for offensively gifted players who was relied upon to score back in junior. That is why either you draft all around talented prospects or if you instead draft an offensive talented player who loves to create, do not hold them back too much but try to reward them if try harder doing certain things that can help their game to be better all around. I remember that someone said that one can function best when he or she can neglect all the negative energy and focus solely on the positive thing because that is the only thing can propel one ahead and have peace in mind.
It is important to coach/teach and held players accountable without favoritism, but it is equally important to reward, encourage and make them feel positive. Not all people deal well with negative energies that well, especially those who are quite insecure or immature.