Why is “speed” a gray skill for DC players?

[Toxcatl]

If your happy to have players with seriously warped stats after a few seasons, that’s up to you, but I like my players to have high, balanced stats.

It is either high or balanced, not both at the same time. Highly-specialized players versus all-arounders. And since a player can't play two positions at the same time, it is better to train him to do one job really good.