Well, ostensibly there would be a limit of however many officers would qualify for such a trait... I'd figure maybe five or six per major, tops. At that point, it would not be worthwhile to keep them in formations other than those the player wants to keep on the move. Especially given a full OOB (Theater, Army Group, Army, Corps, Division), and how it wouldn't trickle down effectively, the ideal/logical place would be in the commands that are going to need to move quickly... which essentially limits them to the Armored and Mechanized divisions. I mean, unless you really want your high-speed, low-drag commander in charge of grunt infantry.
but thats why the trait was renamed in the first place...
more speed for infantry would be very powerful though. ever seen what happens when your units attack faster then the enemy can retreat?