Not sure if this is was intentional but when i was playing I noticed that if I drop a unit that has a 0 entrenchment into a unit that has an entrenchment level (really doesn't matter the number) the unit that I dropped in will have the same entrenchment level. If I then remove the new unit, it will retain the entrenchment level that it received from the previous unit.
My two random ideas I thought of last night are to add an area to write notes about a unit or leader. Make a little note pad when you click on the icon and all of the leader data shows up. The note pad can be right underneath. Something where you can write something like "Grant attacks Memphis no later than JUN 61 in order to open supply lines on the Mississippi River or something like that. The other idea is maybe add a to-do list somewhere so that we can write down things we want to do in future turns. Just my random ideas.