Special unit for different doctorines

So we all know doctrines gives buff and cons to certain army but i wanna propose this

"A new special unit for each doctrine in the secret research"

With that i want some sort of special unit like different doctrines can't make the another different doctrines special unit.

About the special unit i want the doctrines below to have this special unit

Axis: Land kruezer

Pan Asian: Air Craft carrier submarine (only cary attack bomber, naval bomber, and interceptor)

Allied: (idk what to add chose it ur self dev)

Comintern: Flying tank no i'm not joking a flying tank that drops Light tank/Medium tank

So thats what i suggest to make doctrines more interesting hope you add it dev.