It's a game, there is no realism. None what so ever. Arma2, RO2 ect aren't realistic.
How ever to make the game balanced (or what i like to call realistic in game) yes the weapons are very accurate, how ever the M1garand, Mousim, Kar98 were very accurate weapons, In fact the British army's SA80 can only effectively engage a target up to 300 mtrs in a single rifle man role, At a section level it can engage targets up to 600mtrs effectively, only through sheer rate of fire and rounds in the air.
The rifles used during WW2 were accidentally designed on today's marksman level weapons, Engaging and neutralising threats at 600mtrs in a single rifleman role and at section level 900mtrs (suppression)
So it's not so much accuracy you want to change its the velocity (power at distance) or the accuracy of each player class, Not to mention skill set.
Yes a lot of these suggestions wouldn't work in game, and couldn't be implemented, or wouldn't be used effectively by members of the game, how ever custom games be it CLAN, or MODDIFIED GAME it could be implemented, Mainly by the latter.
So! strap in it's a long one.
Rifleman: per say would be extremely proficient with his standard issue weapon, In both accuracy, Rate of fire and reload ammunition carried would usually be around today's equivalent of 4 bandoleers (spelling?) witch would be around 320 rounds, two grenades, 1 smoke.
Machine gunner (bipod): would be proficient at suppression, so dispersion on his MG would need to be increased and velocity reduced, to give accurate suppression and not marksman capabilities. The SS MG (bipod) on single mode can be used as a sniping weapon in game, but in reality the single shot was mainly used for ranging a target of opportunity 3+ men, In the CQB element of warfare the Single shot would be used to suppress opportune points windows/doors mouse hole (hole in wall roughly the size of a man depending on ordnance that made it) even vehicles, from soft skin to armoured hulls (believe it or not, as a machine gunner in todays army your told to engage a tank to kill it's means of viewing hatches, rangers, glass ect), as to not waste to much ammo into a small areas. (Bar shooting tanks, how ever the gunner would equip efficiently for such a task before hand.)
Assault class: This is tricky, the main thing for assault would be not to change the weapons ROF and velocity (rate of fire) but to bring back the amount of ammunition carried by the unit, It was standard for most SS troops to carry 3 magasines when assaulting a building, and 3 grenades 2 smoke and 2 signal smoke, once the initial (knock) - Entering and securing at least 2-3 rooms had happened, a guy like Uppem from saving private Ryan would bimble up with more magazines for him, Not to mention the efficiency of grenades would be increased, Mainly on speed of equipping, but accuracy would be vastly improved due to narrow deployment in buildings as well as distance.
Squad leader: Carrying a little more ammo than the assault troop due to being stationary for long periods of time, and usually behind his assault class his ammo would increase, the accuracy of a Squad leader would be tricky, as many Squad leaders during ww2 would have been the most experienced veteran in his section at that time (stepping up when the current leader was killed.) so efficiency with his weapon would diminish due to lack of usage. Tactical awareness would be increased from the T1 + T2 + T3 view in game, Assault here, Defend here to the deployment of small Mortar barages, usually 3 - 4 rounds FRAG for troops, Not only that Ammunition states would come from his men regularly to know when a re-sup would be needed, This how ever is more for clan matches and serious team workers. This class is ok.
Commanders: Believe it or not weren't efficient with any weapon bar their side arm, The basic marksmanship was there to maybe effectively use a weapon at a range of 300mtrs in single role, this means he shouldn't be able to shoot through a window over this distance. Officer training back then consisted of protocols, map usage, usage of men machine and tactics, shooting was employed but no to the same level as a Squad leader downwards. How ever his situational awareness would be vastly increased, more so over his current level in the game, It was known that a good commander could call in artillery on a single trench system (around 100mtr sq), You might not think this is amazing, but for those times it was a very rare skill on both commander and gunner operator behind the front line. The knowledge of troop positioning would be increased (maybe he could call a hint in, the game quickly sums up players positions after a UAV and shows a nice big arrow on best line of assault only suggestion i got), as well as danger zones (zones of high enemy activity) The employment of deffencive posture would need to be improved, maybe key personnel (squad leader mainly) would have more of an effect on a lock down as opposed to the grunts, due to the squad leader being able to asses the situation beyond the target and draw up a plan.
I don't make games, or pretend to know the best way to improve them, I'm a current serving soldier of 6years and various tours of duty, when it comes to soldiering it's all i know.
Tell me what you think, sorry if it bores you.