I think we have different opinions, I would never build E8 over the regular Sherman. If you really need AT, you can just build Jackson. If you don't regular Sherman can do most things E8 do, and better.
Increase the utility of the unit, like vet 1 ability a timed ability that suppress but does little damage, increase performance vs enemy light vehicles...
Replace Ostwind with Stug so that Ostheer get an indirect fire support unit in T3. Move Ostwind to T4 and buff so that it can be used to support Panthers. Make Brumbar doctrinal similar to KV-2 maybe (it was superior). These solution will fix a number of units and problem.
Well, we are proposing to reduce B-4 damage (like wiping all units) and giving it some utility by doing engine/weapon crit, stun or something like that, so precision won't be that necessary.
By definition, panzer grenadiers are a mechanized infantry, so it has to have any relation with mechanized corps, that's why he is behind tech 2 where there are light vehicles.