as Tobis already mentioned, the real issue of the old doctrine was being able to skip t3 and t4 just by getting some pumas to shutdown the light vehicles, followed by a very fast command p4 to finish the game. This isnt possible anymore with CP4 requiring t3. If people would just spam pumas again they have 0 tanks and extremely delayed tech
This is commander design issue/consistency and not a balance issue. Having Puma (build-able in t2), CPzIV (call-in) and Panzer J (build able from HQ) all having different ways of becoming available makes little sense and confuses things for no good reason.
Having to built T2 to get access to an doctrinal vehicle make little sense, is rather unique and
very restrictive.
All 3 units can become build able from HQ and have different tech requirement. That will make them more consistent while increasing built diversity at same time.
When it comes to the commander design I had pointed out that no tech call-in with good AT and good AI should not be available in the same commander a long time ago.
Actually in order to fix commander one should set some rules and redesign many commanders.