Mobile defense doctrine is useless and it is not used almost at all.
My suggestion of rework:
0 CP - Osttruppen
0 CP - Counterattack
2 CP - 250 mortar half truck
3 CP - Puma (deployed from light mechanized with no extra requirements)
7 CP - Comand tank
Osttruppen at 3 cp is useless. They should be deployed the same in the same fashion other doctrines use them.
Puma should not require Tier 3 tech. OKW deploys them the early game and this is where they are meant to be used (counter to stuard, T-70, and so on). Oster should use them in a same way. In T3 oster has stug so it is pointless to have puma there.
Mortar half trucks fit theme of doctrine well. They are mobile infantry support. They can relocate and provide essential support and then run away when the situation gets too hot. They are amazing units and only 2 doctrines have them. It would be nice to have it here too.
The plan is to play T2 hard and postpone T3 and T4 to get more fuel to spend early game.
Player can resign for grenadiers and use osttruppen as an alternative.
When we get to T2 we want to start spending fuel as soon as possible. 222 cars, 250 mortars, and puma will provide a versatile palette of mobile early game units.
The player should aim to win in the early game as they have no late-game bonuses.
They can exchange their fuel in T2 on a large fleet of vehicles to ensure this goal.