I thought about this topic a lot also. I play both sides. More allies due to axis team being overfilled most of the time, but still.
Generally
I agree with Mr Death. A combination of things.
Team organization
Team work is slightly (but not by much) lacking on the Soviet side. When it gets its act together, it can start to win. But even then it seems to have to struggle exceptionally to get these 'almost did not win' situations. On the German side, the only time I really feel like one has to struggle hard and do team work, is to capture the grain tower on "Grain Elevator" and capturing the first two objectives on "Station". Need smoke and combined effort there. The other maps and objectives just come naturally by running towards the (often large capzone) objectives and shooting stuff casually, and there is no real need to coordinate to achieve it.
Equipment
Blabla. Wrote tons but burned out. To summarize, the germans have an equipment advantage in the assault class (MP40 and MKb40), where they enjoy weapons that have much greater endurance, are easier to use and have much more flexibility (range). The Panzer IV unquestionably is superior in performance to the T-34 also (endurance, protection, weaponry, situational awareness).
Pavlovs House
The main issue is the sun is low and RIGHT BEHIND the German apartment buildings shining in the north-east direction. It forces a single strategy for the Soviets to have any success. It favors the Germans.
The Soviet view of the German buildings is nearly blind. The buildings themselves appear as a large hazy dark shape, surrounded by intense bright sunglare. Gentle moving smoke appears in front of most of the buildings. German soldiers will be in the shadow at all times with a shadow building interior as their backdrop - the most ideal concealment possible. There is no siluetting anywhere. There are also a large amount of windows with padded sandbags as real cover (as opposed to just concealment) and several balconies where one can conceal oneself and shoot from the prone position with a machine gun or whatever, while affording an excellent view over the combat area. Soviet intruders are unlikely to reach anywhere near most of the positions also, making it a stable firing platform.
The German view of the Soviet side is the exact opposite. Full view of almost all their buildings, with the sun shining in such a way that anything appearing on the side of the buildings towards the Germans, will have to stand in direct sunlight, while simultanously the backdrop will always be a dark shady room. This is the worst possible camuflage situation, as any soldier will be maximum lit up (with their bright tan uniforms), while siluetted strongly against a very dark backdrop. It is strange to see all those windows and positions available to the Soviets facing the Germans, without ability to use any of them.
The combined result is that Germans have ideal concealment, cover and fields of fire, while the Soviets have the exact opposite condition. The German team is able to provide very powerful and effective supporting fire from these buildings to help their own team out in the field, while taking no casualties. Soviet support from their buildings is simply not possible. They must stay underground, out of sight, unable to support their own troops, and face great difficulty & casualties fighting in any of the buildings (own and middle) as the buildings are greatly exposed to the German long range firepower.
The tank conditions favor the Panzer IV gun, optics and hull MG performance, as well as the sunlight, and the starting conditions of the Germans. Their tanks may drive hidden behind buildings on the entire west side, appearing from behind any building of choice with the firing lane of choice, with the sun behind them, and ability to shoot at all the center and Soviet buildings with impunity from the west. They also have easy access to a munitions depot on in the north-west with numerous hull-down positions scattered around.
The strongest option for the Soviets is to avoid the open square and any attempts to shoot from the buildings. Instead, take the T-34 with infantry into the south streets where the tank is able to provide enormous firepower (remember, has huge amount of HE shells) directly on the German apartments (optics and the sun is no longer straight behind), suppressing any MGs that may be there and prevent the German infantry crossing the street to the central buildings. At the same time, the firing lanes of the Panzer IV are restricted and the T-34 is not easily flanked. It may move even further south and attack the German apartments from the south where the field of fire is good and the sun lights up Germans instead. From there, the field objective is no longer a problem and the German will be fighting a hard defensive battle.
The Soviets have a small handful amount of positions where it may shoot to the south, or even slighly south-west, without being in direct sunlight. But the lanes of fire are very limited and the spots have zero cover (wood or thin brick walls only).
If the sun position on this map was changed, balance would swing rapidly. I wonder if it can be modded, or the devs could be talked into changing the sun location to be from the South-East or East instead.
Station
The first objectives requires effort, but after that the SMG & assault rifle superiority and having objectives that cannot be lost once taken - just run into the buildings like madmen, and along the sides, and through the underground to appear in the rear and shoot at anything beige. Having a cohesive defense as the Soviets is just impossible after the first objective falls. So many MP40 / MKb40 rambos appearing from the rear, left, right and front.
The underground tunnels are not useful for the Soviets as not only are the objectives not possible to recapture, but often automatic dismemberment results in trying to flank the Germans from behind (peculiar one sided situation).
The assault class superiority is helpful in the open western parts also, due to better long range performance than the PPSh troops.
The walkway bridge in the north is useful for achieving a dominating position (both recon and field of fire) over the whole western half of the map. One can see and shoot the Soviet spawning soldiers from there, too.
The German camuflage is also an advantage indoors and out.