Would it be possible to adjust the scale of the elements from brigade to regiment / battalion, and change the command system to include division forming?
For clarity, an example of what I'd like to see:
I build several regiments (depending on the nation, Britain would have to have battalions instead), infantry, artillery, cavalry, engineer, etc. I send in a leader and enable division command for him, allowing me to form the regiments into a division. Once i have formed a couple of these divisions, i send in a corps leader and form them into a corps.
The benefit of this type of system is that it would, to my mind, allow a more accurate simulation of the changing nature of divisions during the war.