Use the following trick if you dislike the missions were you must take control of all the men on the field. Place all your men in one group. If you have a group of men make as many groups as needed. Keep the person you want to control out of the groups. Turn all the tabs on the soldiers interface to the left (for example, "Free Move", "Open Fire", etc.). Take your men near the battle and select "Disband" (the button with four small triangles). Watch as your men become skillful soldiers.
Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. Use an archival utility such as WinRAR to extract the files found in the "game.pak" file in the "\ubisoft\faces of war\resource" directory. Specifically, extract the "tactis.dl", "normal.dl", "hard.dl", and "easy.dl" files in the "set/difficulty" folder in the "game.pak" archive file. Use a text editor to edit the extracted files and change value under the "ally" header in each of the files to the following:
ally health_increase 40 health 40
Add the modified files back to their original locations within the "game.pak" file with WinRAR or another archival utility.