Just telling you that OKW hardly changed from when they were released, the munition was first changed from 66 % to 100 % and then back to 80 %. Sturmpios were changed from a mid ranged squad into a close combat squad and Kübel got overbuffed and then nerfed again.
I personally liked okw play in the alpha more, it was a faction where your focus was to deny map control of your enemy while you hold your 3 important territories. That was a really interesting way to play and it's sad that relic made okw like the other 3 factions instead of tweaking their original design.
And Obers were Nerfed. The T4 trucks range Pen and DPS increased. The Luchs went from a STs squad sitting on top of it taking no damage to an unholy AI death machine. The Panther went from an equal fuel amount of units being on par with it (per the Elbe Day changes) to being stupidly powerful again with its frontal armor restored, its Blitz returned and its Pen that it got to offset the armor nerf still intact.
Meanwhile alot of the USF easy win counters were nerfed as well (Cap isnt an insane AI unit with his Tommy, cant one hit trucks with offmaps, Easy 8 costs more etc etc)
I played OKW then like Oz but as soon as the Panther got his frontal armor back I just couldnt stomach it. Essentially Muni was given back allowing Shreks to be easily acquired and everything in T4 including the building itself now overperforms for cost. With the exception of Obers not by a huge amount but they all overperform.
So now T4 with the Medic truck is a no brainer. Between Volks and Obers with an Optional Luchs/Panther you have the best OKW has to offer in the AI/AT department. Much less risky because everything listed is much more durable then its peers and much more rewarding then any other OKW vehicle Tier.
Meanwhile with the Truck being what it is it allows OKW to hold down 25% of the Map from the USF until late game so OKW can blob without worrying about losing too much map control.
TLDR there are alot of changes that are fundamental to the current meta that you didnt identify.