The Russian mgs doesn't lock down areas like the German one. Look at its arc of fire.
If they had 4 man squads they would need a larger arc, then it might as well be an mg42. I like the way it is. It makes it feel different and get used different.
IMO it shouldn't stay the way it is because 6 man squads also make german snipers worthless. They cost 340mp ( ithink ) and have to contend with six man script squads and six man weapon teams. It takes forever to decrew a six man maxim ( or at least force retreat ).
On the other hand, the Russian sniper team only has to deal with 4 man gren squads and 3 man support teams so each shot carries far more impact. ( if the Rus player decides to even build snipers.. most just take out support teams with a scout car/flamer combo ) .
In my experience, when I play as the german army against just one productive sniper I feel a strong and immediate need to get some kind of counter to the sniper. As a Rus player against one german sniper I don't feel the pressure to do anything at all. If I built T2 and not T1 I don't feel any strong need for back teching just to deal with it.