About the OST panther, why not simply switch the panther and the tiger?
The tiger could be refit in a generalist role (in fact it is already today), the unit would provide more interest in building your T4. On its side, adjust the Brumbar maybe to be a cheaper IA dedicated unit, reducing its armor or health and global dps, something you use in addition with the Tiger.
Then the OST Panther could be use in doctrines as the OKW command panther is, with some adjustment, making it a really dedicated AT unit, increasing its AT power and reducing its AI one and of course increasing its frontal armor.
The unit could be limited to one at time and only available once BP3 is researched.
So we have an Ostheer faction that has easier access to better generalist units around their dedicated AT units (pak40 and Stug) and if their really need another AT source to fight bigger cats such as Churchills, they can either call an Elefant (in teamgame) or a panther (1vs1)
This would also make other than Tiger doctrines more appealing since you could always build a Tiger.
