Balancing 4vs4 will never break the balance of 1vs1. Ever.
Just try to give me one good example where i could be wrong. Just try...
One Example?
The Elephant or the Jagdtiger are good examples. 1vs1 they are mostly useless and 4vs4 they are OP like hell.
Arty of all kinds. Because 4vs4 has more clumped up troops, because the front a single player has to cover is smaller.
HMG`s, Paks are easy to flank in 1vs1 because of the larger front per player, that means they are stronger in team games than in 1vs1.
Medium Tanks are good flankers that makes them stronger in 1vs1 than team games. Because if you want to flank in 4vs4 you just run into the army of the enemy’s neighbor. And mediums are bad in headon fights.
Short range units like Shock trooper are better in a 1 unit vs 1 unit engagement than in large scale battles, because before they can close in they get focused down by the complete enemy army.
In 4vs4 the retreat paths are longer, that means forward retreat points are better in 4vs4 than in 1vs1.
In 4vs4 the team can carry a player until he gets out his big units.
Certain commanders have special weak points, if an WM player goes elite Doc, the soviet player can safely choose an on map arty commander because the WM Player has no off map arty in 1vs1. In 4vs4, at least one enemy player always has an off map arty to destroy on-Map artys or Pak43 emplacements.
Micro intense units like snipers are better in team games than in 1vs1 because your army is closer together means you can easier babysit them.
Heavy Tanks like King Tigers, Tigers, IS-2. If one is protecting one Victory point in 1vs1 I just take the other 2. That way I force my enemy to send his big tank all over the map. In team games the other Victory points are most likely defended by other players.
I think that are enough examples of things that just behave differently because of the different nature of the game modes. That means if the units, commanders.... are balanced in 4vs4 than they are unbalanced (OP or UP) in 1vs1.