If the progression lines aren’t drastically reworked with other campaign additions (medics, light vehicles, weapon side grades), then going the route that Stalingrad started with captured weaponry like the MP 717(r) would be a good start since both the USSR and Germany captured large amounts of weapons between themselves but would effectively add duplicates within the tree in the name of balance/historical accuracy that might be offputting to some people.
It just requires that they move the 72 round submachine guns up while filling in their spots with lower capacity weapons to reduce the speed of powercreep with the addition of moving the rarer weapons from the tree that precede them and prevent anything “lesser” than them from being added as a non-premium into the gold order roster (AVS-36 in relation to the SVT-40, MKb 42 (W) with scope mount/MKb 42 (W) in relation to any semi-automatic sniper rifle/future submachine gun, etc).
This is what I came up with in sticking to the current format of the campaign trees:
Level |
Class |
USSR |
GER |
Level 1 |
Rifleman I |
Mosin M1938 |
Gewehr 33/40 |
Level 2 |
Assaulter I |
PPD-34/38 (box) [25 round magazine; 920 rpm; 7.62×25mm Tokarev] |
M712 Schnellfeurer (20 round magazine; 900-1000 rpm; 7.63x25mm Mauser) |
Level 5 |
Weapon |
TOZ-B |
MP-34 (ö) |
Level 6 |
Radio Operator I |
Karabinek wz. 1929 |
Gewehr 242(f) (MAS-36) |
Level 10 |
Gunner I |
Madsen (25 round magazine; 500 rpm; 7.62x54mmR) |
Leichte MG 116(f) - (FM 24/29 [25 round magazine; 450 rpm; 7.5x54mm French]) |
Level 11 |
Weapon |
MP-40 (captured) |
MP-40 |
Level 13 |
Weapon |
Browning wz. 1928 |
ZB-26 |
Level 16 |
Weapon |
Sniper SVT-38 |
Sniper Gewehr 41 (W) |
Level 21 |
Engineer II |
SVT-38 |
Gewehr 41 (W) |
Level 24 |
Sniper II |
Sniper SVT-40 |
Selbstlade-Zielfernrohrgewehr 260(r) (Sniper SVT-40) |
Level 26 |
Assaulter II |
PPD-34/38 |
ZK-383 (40 rd) |
Level 27 |
Weapon |
SVT-40 |
Selbstladegewehr 259/2(r) (SVT-40) |
Level 30 |
Weapon |
PPD-40 |
Maschinenpistole 715(r) (PPD-40) |
Level 35 |
Weapon |
DT-29 |
MG-34 Patronentrommel |
Level 38 |
Assaulter III |
PPSh-41 |
Maschinenpistole 717(r) (PPSh-41) |
Changes:
Mosin M1907 replaced by the Mosin M1938 [moved from Level 10] (Level 1)
MP-28 replaced by the M712 Schnellfeuer (20 round magazine) (Level 2)
MP-38 replaced by the MP-34 (ö) to lessen redundancy (Level 5)
Mosin M1938 moved to Level 1 and replaced by the Karabinek wz. 1929;
Pre-war Kar98k replaced by the Gewehr 242(f) to lessen redundancy (Level 6)

MG-13 replaced by the Leiche MG 116(f) and moved to gold order weaponry (Level 10)
PPD-34/38 replaced by a captured MP-40 (USSR) and moved to Level 26 (Level 11)
Winchester M1985 replaced by the Browning wz. 1929 and moved to gold order weaponry (Level 13)

Pre-war Kar98k replaced by the Sniper Gewehr 41 (W) to lessen redundancy and to provide balance against the SVT-38; This shouldn’t have been a premium weapon (Level 16)
Level 21 kept the same
Gewehr 98 with scope mount replaced by the Selbstlade-Zielfernrohrgewehr 260(r) to provide balance against the Sniper SVT-40 (Level 24)
MP-35/I replaced by the ZK-383 (40 rounds) and moved to gold order weaponry (Level 26)

Radio Operator II replaced by a weapon unlock; AVS-36 replaced by the SVT-40 and moved to gold order weaponry; ZH-29 replaced by the Selbstladegewehr 259/2(r) and moved to gold order weaponry (Level 27)
Assaulter III replaced by a weapon unlock; PPSh-41 replaced by the PPD-40; Beretta 38 (20 round magazine) replaced by the Maschinenpistole 715(r) for balance and as Italians were not present* at the Battle of Moscow (Level 30)
Level 31 completely reworked to something else; Sniper AVS-36 and MKb 42 (W) with scope mount both moved to gold order weaponry
Kiraly 39M replaced by MG-34 Patronentrommel as Hungarians were not present* at the Battle of Moscow (Level 35)
Assaulter IV replaced by Assaulter III; Fedorov Avtomat and MKb 42 (W) replaced by PPSh-41/Maschinenpistole 717(r); both moved to gold order weaponry