Doctrinal emphasis determined weapon and aircraft design priorities, which fed into capabilites at the sharp end. Soviet doctrine was big on operational interdiction and strategic envelopment at the start of the war, but shifted to close ground/air coordination with a CAS focus as the war went on. German doctrine included all three mission types but was mediocre at all of them. US doctrine was big on operational interdiction and strategic bombardment but did not include CAS missions or ground/infantry coordination as a priority. I'd also prefer to see mission performance more heavily impacted by doctrine with some missions only available if you go down a specific doctrine tree. Armor division without logistical support provided by soft skins in the rear echelon units is expensive fortress infantry division. Cannons VS rockets seems like an important distinction, but only if you're looking at pure tank attack power as opposed to ability to degrade or destroy the ability of an armored division to act, in which case they're pretty equivalent since your main target is soft skinned support vehicles. The rest is incremental mission performance upgrades. Stuff like Soviet PTAB should probably be focus gated like Japanese long lance. Most planes are designed to carry multiple weapon systems and can flip between them on the fly as mission requirements change, but they're usually only going to change engines as part of a major overhaul. I'd also focus most of the design and tech on the engine as opposed to the weapon systems. And if you can't build a high performance engine that can carry a solid airframe you're probably not going to be able to handle other missions (ex Zero). You can make a heavy but still powerful single engine fighter (P47 thunderbolt for example) or a relatively light twin engine (p38). Single, twin and quad engine would make a lot more sense than light/med/heavy air frame as far as airplane design goes.

Tungsten warzone 2100