For comparisons sake, 22yo Darcy averages more possessions, goals and marks than 30yo Stanley this season despite coming in off injury and playing mostly forward. Stanley has only averaged 2 more hit outs than Darcy too.
For their careers, Stanley averages one more touch but 2 more marks while Darcy averages 12 more hitouts and a tackle more per game. I dare say the kid playing against men for most of his career shouldn't be anywhere near Stanley's stats for any of those figures.
From a playing point of view, Stanley is terrible in the ruck and relies on having midfielders at his feet who don't need him to win the tap. That way he can try and use his athletic ability around the ground to be another link in the chain although he's not very good at that and isn't a great kick. Alternately, Darcy actually wins the hitouts and is learning exactly where to place them to be most effective. He's good in the air and really improving his contested marking (which is way ahead of Stanley) as well as starting to hit the scoreboard and get around the ground more.
I don't think there's a coach in the AFL that would tell Darcy to play in the 2's behind Stanley.