...And here we come to the problem, that the game heavily favours short range units, assuming they can close in unharmed enough (which Riflemen can at vet3, thanks to their received accuracy)...On top of that, DPS differences at long ranges don't differ as strongly as they do at short ranges - in other words, a short range weapon is usually massively superior to a close range one (compare BARs to lMG 42s) at close range, while the long range weapon only makes a relatively small difference at long range (again, compare BARs to lMG 42s).
This is of course not exclusive to Riflemen, considering the general problems of focus on long range vs. short range units
...a nerf to the long range performance of close range weaponry would be in order - and here we could also finally implement the difference between assault rifles and SMGs, by differing their damage profiles.
I cannot see by this view point at all - PPShes, Grease Guns, Stens and MP40s (no matter who holds them) do less DPS than Conscripts' infamously low-DPS Mosins at long range and Para Thompsons are basically the exception with more or less the same DPS as the aforementioned Mosins at the cost of basically being the most expensive SMG squad in the game. I would thus conclude there is definitely not such an issue with close-range weapons across the board.
I also find assault rifles to be sufficiently different from SMGs - they will tend to win a fight that starts at max range against SMGs, are less advantaged the closer the fight starts, and the mid-range DPS is noticeable (aside from Sturmpioneers where I regard that as an issue needing fixing).
I really feel like what you're saying applies to
only BARs.