Everyone here except Alex knows majority of the Soviet commanders are hardly competitive. You will see Lenny or Stephen try out random strategies here and there. We all know how most Allied games go; USF Airborne + EZ8s and SU goes Shock front line or Guards. As for Axis well, the commanders choice are just an icing on the cake as your stock units and all tech structures give me variety of choices.
Guard motor
Shock motor
Counterattack tactics
Mechanized support
Shock rifle
Advanced Warfare
Terror Tactics
Shock Army
Honorable mention to Urban defense for 6 minute knock outs.
All in total 8 (9) viable commanders, which are literally more than OKW or USF even have.
Lets look at Ost;
Assault Support
CAS
Lighting war
Spearhead
Mechanized Assault
Luftwaffe support
Fortified Armor
Jeagar Armor
Honorable mention to Oustruppen and Mobile Defense.
All in total 8 (10), viable commanders.