There seems to be some misconceptions here that I remember trying to clear up back when the new SMGs first came out, which is leading to a lot of clueless arguing. I'm not going to get into all of the rest.
There are a few things to know about the weapons that came out at that time and how they compare to others before people start complaining. The two big ones are that the new SMGs are not coded in the same way as the old ones, and that the eye relief of the new guns (and for some reason around then is when they changed the m1 Garand as well) is different than that of the old guns. Hopefully I can explain how this affects the performance of the guns and the way CRS behaved.
First off, the different way the accuracy of the guns are programmed. As most of you have probably noticed, the rifles in this game might as well be lasers. There's bullet drop, but otherwise the shot hits on point pretty much every time, with none of the dispersion you'd expect to see at range. It's been awhile since I've bothered with LMGs so I can't comment about it too much, but the old SMGs had their bullet dispersion cranked up to 11, producing a horrible lack of accuracy even at 25-50m when firing even a single shot. All of them do this, but the MAS38 fires so quickly that it doesn't matter, while the .45 ACP rounds in this game do too much damage on top of being fired from the fast Thompson. So in the original SMG lineup, all guns are way too inaccurate, but the MP40's relatively slow rate of fire and only a 9mm cartridge make it so that it's not very impressive.
In contrast, the mp34 and the M3 and Sten don't have this ridiculous amount of dispersion, and act much closer to how they should in real life compared to other guns. That's why we have people in this thread talking about how the mp34 has to be fired in single shot, because they are reacting to how much differently it performs to the MP40 in both accuracy and recoil (the mp34 has to be way too high). Despite this, the Sten is a relatively stable gun that also uses 9mm rounds so it's not too bad, and the M3 has a slow enough rate of fire that a 2-3 round burst can be accurate (just like the other guns in this lineup) and deadly because of the .45 rounds.
Unless CRS brings all SMGs into line with way they do coded randomized dispersion, you're still going to have a problem with the guns performing much differently than each other. Any weapons audit by Scotsman has to address this.
Secondly, for some reason at some point CRS decided to model the art for guns to have a different eye relief once they started putting in new guns again. They did this across the board and for both sides. In the original guns, the eye relief was very close to the sight, giving you a clear picture of what you were looking at. This was moved much further back with the new lineup, for rifles and SMGs. With the german weapons you hardly notice it because of the way the rear sight aperture is designed, with its open sights. With the allied weapons though they all have a peep hole sight (you know, that closed metal ring), which caused huge problems with the new guns and required an immediate patch to fix them so that they were actually usable, as the area in which you aimed was so small and obscured that you had to hope that you were pointing at the enemy after moving your sights on him. This is why you saw immediate action to fix the artwork for them (and the Garand) but no other substantial changes afterwards.
To be quite frank I don't understand all of the complaining. The new guns aren't substantially better than the old ones for someone who knows what they are doing and if you really wanted to remove the late war guns you could simply pump up the original SMGs to match totals across forces. Personally I don't care either way, but really all you're doing at that point is taking away toys from one side without any impact on balance, in a game where we already currently tweak or ignore historical accuracy.