g43 and stg I'd say are about equal in different dmg profiles.
For g43 you have the mainline and "special" g43s. As you said you have two completely different damage profiles based on squad, and the game doesnt tell you that.
For STG44 you have close range STGs (Strums), Mid-close range (Pgrens), Mid-Long Range (Obers) and a dmg steroid at all ranges (Volks). Atleast the Obers one is slightly different than the others.
The only other weapon I can think on the allied side that can be confusing is the m1a1 (elite vs RE) for USF or the special Commando Bren for UKF. But I'd argue that one is nowhere even close to as confusing as the Axis ones.
I mean plenty of people on this site have gotten it confused by this (including me) and I'd say the players on the site generally know damage profiles and statistics better than the average player. An average casual player has no chance of knowing that a strum stg is different from a volk stg or a Gren g43 and a JLI g43. Which would explain why a lot of players will always try to get up to point blank with volks/obers when they have stgs. Even if they would be much better of sitting in cover and making the opponent close on them.
Its not just the damage profile in the G43's case, though, their functionality is totally different between squads. The JLI G43 actually has an inverse DPS curve like an LMG, as well as the aformentioned crit-snipe.
Also: For Obersoldaten STGs, they're a different weapon, you can tell at a glance that they'll act differently to the Sturm/Volk/Pgren one due to the model's massive IR scope. The damage curve for the Ober STG is broadly the same as the Pgren STG incidentally, the real difference is in the partial cover negation of the Ober STG, which is broadcast, again, by the massive IR scope.