USF gets free squads
Wher gets free access to grenades and upgrades
Ussr gets 6 men squads
Brits get base arty
OKW gets:
1. vet 5
2. Free access to grenades and upgrades
3. Effects of field HQs
4. Scavenge
5. Better armor then any other faction
This isn't a problem with OKW getting a bonus like the other factions. The problem is the have TOO MUCH bonuses.
I do want to point out that while every faction has a Pro over the others, they each have Cons as well. So just theorycrafting about one section of a faction's design does not hold up in game. Ostheer has to tech through 3 levels to get their best tanks, while Soviets don't have as good stock armor as other factions, USF has no heavies and their early AI stuff(Lt) is split from their early AT stuff and light arty stuff(Cpt), Brits have expensive MP costs and no mobile arty, OKW has bad team support weapons(no non-doctrinal MG), can't build caches(this is why they still have scavenge), no good garrison counter(Leig is bugged to not hit buildings or barrage target), while other factions have flamethrowers or smoke nades or base arty(Brits).
However I could see locking Shreks behind a 100MP 15 fuel upgrade in HQ called Tank Hunter Tactics and cost the Shrek at 70 munis(they are paying 90munis for it, because it doesn't have a fuel cost), but you need to give Volks fausts. So they can counter clown car rush(Raketen can't reliably come out and counter this strat and this has been proven before) as it will rise up when Shreks aren't immediately available. Raise Ober's LMG to 70 munis(Infared Stgs could go to 80 munis). Lock Panther behind Increased Armor Production upgrade in Schwerer for 150MP and 30 fuel(Brits pay 50 fuel for their Hammer and Anvil, but it comes with several additional abilities).