Show me an Ostheer player who uses StuG's and PIV's to counter enemy armor and I'll show you a player I'm about to make my bitch with Jacksons and AT grenades.
Both the Ostheer AT gun and Shrek Platform are extremely fragile, and can be wiped in literally one shot from the basic stock Allied tanks, especially in the case of Pgrens when you can just crush them easily. And in the current ultra-commander dependent meta there isn't a single good Ostheer commander with the Pak43, and a Tiger with support will always lose out to a IS2 with support, or more than a single KV1 with support.
So that leaves us with the Elefant, which is an excellent TD despite the draw backs of it's slow speed and low maneuverability, and the Panther which is gated behind a extremely costly tiering system.
The Jadgpanther (It should be a call in from a commander) would give Ostheer a dedicated medium/heavy leaning TD that while it lacks the shear range of an elefant, has more mobility and a better ROF allowing Ostheer more breathing room.
Loosing to IS2 is L2P issue most of the time. IS2 is not OMGWTFWUUUTGARDENYOURELIC unit. There are many useful commanders against IS2. My best is 9 secs to kill IS2 without Tiger or Elephnat. Bad Pak43 commanders? The one with Pak43, Command Pz4, smoke, railway arty is one of the best. Thanks to this commander I was able to kill IS2 in less than 10 secs.
Tiger + 2xPak40 is a killer against IS2. You dont have to even use your Tiger against it. Focus on support while Paks get veterancy, stun and finish.
Tiger + JU strike
Two very good doctrines with Elephant.
Countless with Tiger.
3 (I guess) with Pak43, one of them is great, two are decent.
And you are saying that Ost has no counter to IS2 except Elephant..
_____
OST needs one simple thing. Reduce Battle Phases costs, increase buildings costs so you can skip T3 and go for T4 without loosing resources. This would lead to Pz4 into Tiger, or Panther+doctrines without Tiger. Right now it's hard to live without Tiger.