His development would be stunted by sitting on the sidelines most nights; that wouldn't be the case with the other two.
Not the case with all players. Giving players a taste of pro culture can make them work harder when they eventually do get sent down.
McLeod was hit by an LBI injury and he's a speedy player. If a speedy player can't play with speed, then yeah, their stats are going to be mediocre. Good news is, though he's not ready now, he's still got a few years of time in the A, and at the very least, he can become a forechecking grinder with his size if he never pans out offensively. This is mid-first-round picking when you draft 18 year olds... you get a real mixed bag there.