I'd definitely like it if you could also just "set their formation" outside of battle ... as an inherent trait of the army group.
Say you have several 'auto-configurations'
1. Priority is on high initiative in the front
2. Priority is on low defense in the back
3. Priority is on low HP in the back
4. Priority is on ranged units in the back (so a sword champ would be in front, a bow champ in the back, and an Ice-staff in the back)
And then you can pick one and "edit" it into a new formation ... as in personalized on a unit by unit basis .. and just have this be the formation for that army group -> Cannot store more than one custom formation. If you switch back to an auto-configuration, the custom formation is lost. If units are removed or added, the custom formation is lost.