There are 18 skaters that play in an NHL hockey game for each team. Of the four major sports this is the most and therefore requires the most work. Typically, a well constructed NHL team needs to feature at least three competent forward lines and two defensive pairs. Anything after that is what separates the good from elite teams. As of the moment, New York has two good forward lines and one good defensive pair.
The rebuild is still in the initial stages for the New York Rangers. A lot of the rebuild still needs to shake out in terms of roster development.