I think managing his minutes so that he doesn't lose muscle / strength over the course of the year is the more forward looking approach. This is of course under the hypothetical that he needs that type of management.
PK minutes is not meaningful for his long run development, in my opinion. In general, I'm not a fan of putting your top scorers on the PK. Yes I know it helped Nash, yadda, yadda, yadda.
Not just a matter of who our current assigned centers are - we have options and don't need to play him there unless it makes him a better player. I haven't seen any reason to think that KJ would be better at center than at wing. He looks great at wing. He already is the primary puck carrier.
Let's not forget that he put out his shoulder last year on a faceoff. That might have something to do with a reluctance to have him take them, at least for now.