The IS-2 has 375 armour, which means only other heavies and the Panther are effective against it.
In a meta where the IS-2 has a habit of being the first built vehicle larger than a T-70, the Tiger is going to be favoured: for a relatively small premium over the Panther you get potent manpower bleed too. Nobody's going to go Panther against the IS-2 if they've got a Tiger.
The problem isn't OKW's nondoc roster, it's that the 1v1 heavy tank rush meta hasn't been successfully killed off yet and the best counter to a heavy right now is another heavy. Until it is, you're going to keep seeing Grand Offensive.
Yet OKW have been using the same commander again and again, going from special ops to G.O. that thus stats as faction are unreliable. They might indicate that the faction is about balanced or simply that the specifics commanders contribute to the faction doing ok. It is possible that they will not do that great without the specific commanders.
As I already have pointed out their win rate without G.O. was as low as 42%.
And what happened if you didn't go Panic Panther in the last meta?
You'd get whacked in the face with a techless heavy.
It's the same problem we've had for a year: stalling for heavies works, so the 1v1 degenerates into heavy tank standoffs.
I'm starting to think the only solution is to make heavy stalling completely unviable. The very existence of that strategy kills off so many others.