Basically I really want to get rid of the Volksgrenadier Panzershreck because I think it enables a lot of bad gameplay. (Not saying it's imbalanced, just that it's a bad idea.) Problem is OKW then needs to receive a bunch of buffs (particularly to anti-tank) to compensate.
Changes I also wondered about:
Flak HT cost reduction to ~40 fuel (to compensate Battlegroup cost increase)
Flak HT penetration increase (but worried that doing so will make it too strong against intended counters, like T-70)
Panzer IV fuel cost back to 135 or so (the current 150 is really expensive for a medium and with more expensive Battlegroup it would arrive later)
If you want to reduce shreck gameplay, better for Relic to create second shreck weapon profile specific for OKW with reduced stats. If you make shreck doing only 2/3 of their actual damage, you already significantly reduce the power of the blob. Actually OKW need 4 volks squads to run over tanks, 6 squads would simply cripple their economy and open a huge breach in the IA department.
Relic is stuck in a bad position with OKW, they can't really make volks more IA performant because there is already the Sturm + Kubel + whatever specialist from doctrine.
Flak HT is a beast vs infantry, almost instant pin anything out of cover and fast enough to kill half of any squad in one volley same in yellow cover. I don't know why you want to remove the setup time, the Flak HT is a defensive unit dealing a shitload of firepower and suppression at the same time in a short time period. In good hands this unit goes easily Vet3+ to late game. if you remove the setup time, you´ll make it completely OP.
You also forget the Puma, which is a great AT unit. Problem with Puma and Flak HT is they are dedicated AT and AI units, really good, but requiring micro. While you can have a-move blob of sturm+volks and then spec squads+volks or obers+volks.
Imo a simple change that could shake the meta would be to move PUMA T1 with Flak HT, and move shreck (but not flamnade) into T3 or available after building 2 HQs.
Forcing players to use mediums + raken instead of shrecks, maybe reducing fuel cost of the Puma, dunno.