From a fan perspective, one of the nice things about having your team hire a top executive from another clulb is that you can look at that team’s history in the draft during that person’s tenure, knowing that while they might not have made every pick, they certainly had heavy influence in the war room on draft day.
In John Idzik and Mike Maccagnan, the Jets hired a number cruncher and a college scout respectively. Nobody outside of each team’s war room knows what Idzik or Maccagnan contributed when draft choices were made.
In the case of Joe Douglas, the Jets got Philadelphia’s Vice President, who would have certainly had the ear or Eagles GM Howie Roseman whenever the Eagles were on the clock.