2. CB Marcus Peters
You could argue Gurley was the best player in the draft, but Peters is my No. 2 simply because he's still in the league. Peters was a mid first-rounder in 2015, going nine spots after Flowers at 18. Like Gurley, Peters' resume speaks for itself. He was the Defensive Rookie of the Year in 2015, First Team All-Pro twice, Second Team All-Pro twice and a three-time Pro Bowler.
The titles are good, but Peters' play is great. Peters has tallied 92 pass deflections, 32 interceptions and even has seven touchdowns in eight years. The Giants secondary has been in question for quite some time and Peters definitely would helped bring some stability.
The alternate history of the Giants drafting Peters is what's truly interesting. What would they have done with that cornerback room? The Giants already had Dominique Rodgers-Cromartie, who ended up a Pro bowler in 2015 and Prince Amukamara, who was pretty solid in his last year with the Giants. They needed offensive linemen, so do they trade Amukamara for a lineman and pair two future Pro Bowlers together? They would have needed a lot of foresight for moves like that, but it's nice to think about, And what about Landon Collins?
The safety was the Giants second-round pick in 2015 - do they just not take him? That's a heartbreaker, especially with how much Collins seems to love New York. Either way, when you look back, you take Peters 10 times out of 10 over Flowers. As of this writing, Peters is still a free agent, so there's time to make things right.