Just to keep in mind... units are together in battalions [or companies... whatever you want to call them.] Eventually, micromanaging each soldier would become nerve-racking and time-wasting as you army expands. You will just want to get into battle, or appreciate the many other aspects of DoF.
That is why I suggested the experience option for battalions as a whole. To be realistic, I think that if anything is done in this area, it will have to be on a battalion-wide scale. I just don't think there would be enough players out there that appreciate such a high level of micromanaging that the Devs would consider implementing individual unit changes.
Also, unless you almost never play, or are a very bad player, or just like having absurdly small armies, keeping up with micro unit changes would be impossible.
Also, just a note: battalions do earn experience porportional to the amount of foes they kill in battle, etc.. in a lull in combat or even after the battle, the player can assiagn which categories these experience points fit into for the battalion, meaning that the player can specialize certain battalions for certain tasks. Also, there is a training grounds in the game, where players can pay in gold to have their units trained [to get more experience].
In DoF, experienced veteran units pack a whallop against their normal opponents, though they are still vulnerable to their normal counters. But Experience points take a while to get, hence the training option that already exists. However, as I said before, I think that this looting system would be an interesting way to supplement training and combat as a means to gain experience.
"Yes... I am writing a book. So far I have the page numbers." - unknown author.