I'd set it up as follows:
- BP1 cost change reverted from 50 to 40 fuel, fuel cost moved back to T1.
- Osttruppen and Assault Grenadiers require T1 built before they can be called in.
- Assault Grenadier cost from 280 to 260 manpower.
- Recharge times and everything else remains the same.
This has the most benefits and not many drawbacks:
- 2 MG42 + 2 Pio builds and T1 with Osttruppen builds not affected (these are not considered problematic builds, nerfing these would just harm diversity, which is what more expensive Osttruppen / BP1 would do).
- Good timing delay on MG42 + 3 Osttruppen builds (1:53 T1 vs 1:48 35sec 220mp vs 1:35 live). Also, most of the added cost is upfront and the Pioneers will be busy building T1 at the start (all add up to a less oppressive early game). MG42 + 3 Gren builds take 2:42 to field.
- Panzergrenadiers and T2 delayed for Osttruppen and Assault Grenadier builds.
- Wouldn't be just a straight up cost nerf to MG42 + 3 Osttruppen builds, but give access to earlier Faust and T1 units.