those bent barrels were put in service for tank crews and were mostly at a 35 degree angle, i think they had a effective range of 35m.
also instead of having one team having a better ration and the other having better weapons etc..
maybe the defending side (Germans in most cases) would be able to spawn in allot more different places while the attackers (Brits etc..) having to spawn by a few static or moving vehicles.
I don't think its likely you'll see those bent barrel attachments in the first release, or second or third . They just aren't very practical.
The allies and axis are issued weapons and gear in accordance with historical accuracy - so its history that tells us who has what, when and where. Remember also that the British and other allies for that matter weren't always the attackers; plenty of times the axis were. Whether it even be a counter attack, it varies.