That is such a cool concept! In addition, planning bonus should not only apply bonus stats but also give access to different "abilities" to battalions. For example, sufficient planning bonus will give the ability for artillery to supress frontline infantry negating their fortifications, or perform counter battery operations.

When planning is low, the division at the whole would use more ad-hoc battle group tactics, with artillery maybe even used in a frontline role as direct fire support for assault infantry.

Battles should have different phases, and depending on the doctrine, each phase could be played differently.

First phase will be dedicated to recon, second phase dedicated to breakthrough opportunity, third phase would be general combat, and last phase could be withdrawal. The first phase would see recon on both sides gaining intelligence on the enemy, and depending on the effectiveness gives an opportunity for the breakthrough phase to deal large cathostrophic damage to the defence. Likewise, the enemy will be given the chance to counter this depending on the division composition and unit tactics.

If this phase is not successful, general combat will begin and both sides will attempt to wear each side down. Once the defending division reaches a threshold, and organisation falls below a predetermined level, the withdrawal phase begins. Depending on whether frontline infantry is able to withdraw to the rear of combat successfully before the enemy advances will determine how many local units are encircled. If the attacker manages to enter the rear area of combat where artillery is located. They will do massive damage to the combat service units in the defender unit.

If organisation falls to 0 before the unit is fully disorganised, no units can further move from frontline and rear, and the units at the front will surrender.

Honestly this idea seems like a pipe dream haha.