It seems horizontal based on preference really, with Ostheer being slightly more self-reliant and versatile but also having less potential to be really powerful if you perfectly craft strategies and synergies. Stug is spammable and has TWP but comes later. JPIV can come earlier, is better but pricey, and has active camo.
One nice thing about the Jagdtiger is doctrine, Panzerfusiliers are great and Sturm Officer goes well with Prostruppen.
I think the OKW only having the Stuka and infiltration nades to deal with emplacements is a design flaw though. The ISG should be able to lay down smoke, and Sturms satchel charges.
