In a preview of the last balance patch, grenadier reinforcements were set to 28 MP. I think this was very reasonable, as tommies are equally expensive for better performance.
This suggested change was later reverted because of the tier4 global buff. But, given the current meta that revolves around not building regular LMG grenadiers, perhaps the original idea was not so bad? Grenadiers at 28 MP would open up all the other commanders again that don't have Osttruppen or 5 man grenadiers.
If this makes 5 man grenadiers too powerful - I'm not saying that it will! - perhaps they can be slightly toned down.
I think this change will open more variety in Ostheer commanders and also be a better overall buff, since the tier4 buff had its capping bonus removed and many 1v1s don't even go to tier4.
At the same time, this change would slightly tone down the Osttruppen Doctrine, which might be a bit too dominant, because it will not benefit from this change and the tier4 change will be reverted.