destroying a schwerer HQ requires a coordinated and patient attack. you cant just rush into it with mediums and hope to kill it. be intentional with what youre going to do.
wether it be sniping it with jacksons, barraging it with 120mm mortars, attacking out of range with at guns while machine guns push off any counter attack, or swarming it with multiple medium tanks, you have to be intentional in destroying it.
the cheapest way to do it is using two 120mm mortars, using at guns + machine guns/infantry is also effective, and the fastest way is probably attacking with mass armor, but also the riskiest since you could possibly lose a tank if there are supporting anti-tank next to the schwerer.
one instance, i had a 2v2 with a mate of mine on rails and metal. i was USF and my mate sov. the okw/ost team was on the northeast side (fixed position back then) and they clearly knew what they were doing. they set up medic truck behind a big house near north fuel as soon as possible and got sturm officer as soon as possible. ost got two mortars. of course in addition to volks, grens etc. the map was cut in half, and we couldn't push the medic hq because sturm officer with two mort literally sniped my mate's two sniper teams in matter of seconds.
so we held back, and contained them when they try to push out from their little hole. i mean we should really get more than half of the map, but crazy sturm buff and medic truck meant no early game combination of allies unit could penetrate it. so mid game comes, i got an AA halftrack and more units, and soviet guy got more units and we get ready for a big flank from our fuel point on the south to their little hq at the other fuel point. i try to get a huge flank in and get in between their forward hq and their base and what do i see?
a flak base just far enough back, but forward enough to prevent any rear flanking of their forward hq.
it halted our advances and we had to wait for the late game because if we tried to go for the flak hq, we would be flanked.
and we got scotts, jacksons, su85s, katushas and we outplayed them (they made many mistakes) and won the game. the cheesest and most boring game ever.
**now, i agree with you that it is counterable etc etc, but the whole okw forward bases lead to such a stallfest and excruciating patience game which is so not fun to play against. i think it is a bad design.
and on another point, i played a lot of OKWs, and you don't need obers and panthers imo, im not a pro. i literally never used obers and shreck volks, sturmpio, pumas, jagdpanzer do just fine.