Germany, starting 1.I.1939:
1 - anybody mentioning "interleaved wheel suspension" gets taken outside and beaten. If necessary I threaten with concentration camp.
2 - I kill the Pz.III and make Pz.IV the one and only chassis for everything. I bring forward the F model, i.e. with simplified lines, wider tracks, thicker armour, albeit with a 7,5cm/L35 or so cannon - it is the one and only tank, the chassis also used for Sturmhaubitze IV and - in modified form - for the Hummel/Naschhorn. The Sturmhaubitze - although otherwise drawing heavily on OTL Sturmgeschutz III, gets a Jagdapanzer IV type of of casematte, not the artisanal manufacturing atrocity of OTL. But I'm getting ahead of myself - production of Pz.III ends before it starts, Pz.II production is cut back, only the Pz.IV gets made.
3 - as the Czech plants are incapable of handling anything heavier, they are made to churn out the OTL Marder III M, with engine in centre of vehicle, in AT - Marder, SPG - Wespe, and Close Support - Grille variants. Of course, the centre-engine chassis has to be designed first - hence the first such vehicles can be expected in units in early '40 (at best). Until then the Pz.38(t) is produced "as is".
4a - if the output of Czech factories does not suffice then the Pz.II would share the load, with similarly modified chassis (i.e. OTL Wespe) used for AT/SPG and/or CS variants.
4b - if enough production capacity - the front-engined OTL Wespe chassis is used for APC instead of the overengineered Sd.kfz.250 and 251. Those half-tracks (with BOTH wheel and track steering!) are killed, replaced with armoured Maultiers using Pz.I or Pz.II running gear (i.e. like Maulteirs in OTL).
5 - not sure if still inside the Panzer supremo brief - but I kill the motorcycle fetish and use the engines wasted on the sidecar bikes for Kuebelwagens and suchlike. Motorcycles are solely for messengers.
6 - again not sure if still inside the Panzer supremo brief - but all interleaved wheel half-tracks replaced with unarmoured Maultiers (see above). Number of weight classes cut down to 3-4.
6a - suggestion of Sd.kfz.2/Kettenkrad is punished by concentration camp.
7 - recce vehicles - maybe keep the Sdkfz.250 as light scout and for InfDiv, and/or or a brought forward Puma is used as the heavy. Or use a modified Pz.II/38(t) variant.
8 - the OdeB of Armoured Divisions is: single Tank Regiment with three battalions, some 150-200 tanks; two MotInf Regiments, each with two Battalions; a recce Battalion with 3-4 coys; Artillery Regiment with 2-3 Battalions (SPG maybe in 1940, certainly in 1941) - that will allow easy formation of 2-3 Kampfgruppe as appropriate.
9 - going by OTL - objective is formation of PanzerGruppe, with two/three standardised Armoured Corps - each of 2 PzDiv and 1 MotInf Divisions (two Infantry Regiments), plus army troops in the form of a 3 Regiment strong MotInf Division.
10 - I arrange for Ferdinand Porsche to be marooned by outbreak of war in the UK or, if that fails, he has an
accident ...
11 - I aim to end war in late '41, by mid '42. I don't plan for later