I am a big fan of the total war serie and when I started playing DOF I instinctively tried to place my units with the usual right-click slide way we do in the total war serie.
The way it works is like this:
Lets assume you watch your regiment from behind;
You select your troop and then you right click somewhere and hold it. The position you right click will define the top left corner of the future position of your unit, then you hold the right click and slide your mouse. The position you release the right click will define the top right corner of the future unit position. Then the unit will start moving at this postion and rearange herself on this position.
It works well on the total war serie because when you do a large click slide, the units will rearange itself with a number of lines of men depending on the width of your click-hold. On DOF, you have t unlock some troops arrangement so it might create a little problem with this way of managing units.
It is probably an idea that have been raised before. I will complete this post with pictures to explain it better. But not right now because i am at work