I'd done this:
- every stationary weapons is emplacement like the brits got (howitzers, pak43's flaks etc"
- pak43 for ostheer and flak 88 for OKW
- give more opel blitz for ostheer commanders, make OKW opel blitz same as ostheer one (securing points etc) and give soviets the ZiS truck or w/e it is called so it is also securing point
- non doc forward HQ that can produce basic inf and optionally weapon teams if required tier is build, reinforce, and is only possible to make it on medium up to maximum sized buildings, and these buildings got more HP, resistance or whatever makes then sustain much fire
- Jumbo sherman for US, doctrinal unit, probably replacing E8 from mechanized
- urban doctrine for soviets that gives all the goodiess for close combat/clearing buildings/big shells so i think of - dbl flamer upgrade for engies, ppsh, better forward HQ, KV-2, booby trap on points
- something like CoH1 blitzkrieg ability for some ostheer commanders, equivalent to others like valiant assault or FMR
- replacing mortar HT for ostheer with standard HT (same model without mortar) that can be upgraded with MG/mortar or simply nothing that can reinforce and carry units
- some kind of bunkers for soviets and maybe concrete bunkers for OKW (something like it was in CoH1)
- Churchill Black Prince a.k.a british KT for brits
- maybe make pak43's and 17 pounders as a mobile AT guns, and slow
- SPG's arty for ostheer, OKW, soviets (US and brits already got suckston and priest)