Reading up on the effectiveness of tank formations, based on total power and such, it was determined that the most optimum formation was generally a 50:50 split between composing forces of armour and infantry. The 75:25 split (armour:infantry) was actually a substantially weaker formation than the 50:50 split, primarily because tanks were at a major disadvantage when attacking or defending without sufficient infantry support. This generally required other infantry formations from other units being attached to the tank units, or the tank units attached to them in ad-hoc formations (like the British formation during the Arras attack).
The early divisions did have more tanks, but they actually were weaker than those with balanced equipment. To represent this, early tank divisions should have powerful Hard Attack, but weaker Soft Attack and Defence (showing their relative ineffectiveness against infantry formations, especially if they have strong AT formations). Gradually the Hard Attack ratio should decrease, while the Soft Attack and Defense should increase.
---------------
(the following changes assume that no other techs to increase Hard Attack, Soft Attack or Defence are researched, but what tanks would look like in regards to doctrinal changes)
As an example, early tank divisions may look something like this:
PRE-WAR TANK HEAVY DIVISION (typical 2 Tank Regiment/Brigades, 1 weak Infantry Regiment/Brigade)
HA: 10
SA: 4
Def: 4
These divisions were generally ok as blitzkrieg divisions, but they were not very good in breaking through strong infantry formations. They have speed, and high anti-armour ability, but without sufficient Infantry support, they lack defensive abilities and are not able to attack strong formations, and could not hold against anything, since tanks were good targets without sufficient infantry support.
---------------
As tanks are taken away, and some infantry added, it would look something like this:
EARLY WAR EMERGENCY DIVISION (typical 1 Tank Regiment/Brigade, reinforced Infantry Regiment/Brigade)
HA: 8 (-2 points)
SA: 6 (+2 points)
Def: 6 (+2 points)
These divisions are basically 'panic' divisions. When it was realized that tank heavy formations resulted in severe attrition (because tanks were vulnerable from infantry) and actual weakness in battle, as seen by the destruction of many French Armoured Divisions, and the 1st Armoured in France, motorized infantry was reinforced, and tanks removed so that there would be an even balance between tank and infantry battalions. It was found that a tank division of 150 tanks was almost as effective as an armoured spearhead as a division of 300 tanks, but was actually a lot less clumsy and was capable of putting up a better defence.
---------------
Eventually, the tank formations will look something like this:
LATE WAR ARMOURED DIVISION (typical 1 Tank Regiment/Brigade, 2 Infantry Regiment/Brigades)
HA: 8 (+0 points)
SA: 8 (+2 points)
Def: 8 (+2 points)
The Germans and Allies found that in France and Russia the days of lightning warfare was over. War was still fast, but as infantry Anti-tank technology increased they became way more powerful. Larger infantry formations were required within Armoured divisions, since they became an antithesis of what they once were, from a unit that exploits a breakthrough to one that makes the breakthrough.
(points at CopperNicus)
