I believe the NY Giants should be taking players that have elite traits or production. If a player has elite athletic traits and exceptional production at the college level, they will usually be a first round pick. In the later rounds, the G-Men need to find players that can do something exceptionally well, and then fit those strengths into their system.
Finding great value late in the third and early in the fourth round can be difficult in most NFL drafts. It is usually obvious who the best prospects are in the early rounds. A general manager earns his salary by finding solid contributors deeper in the draft when the bust rate is quite high.