... no, really?...
Sure you can't use the BAR or MG34 like a .30 cal.
But the difference between DH and RO2 is with the game mechanics. In DH your targets, let say 4 men will reacts to your (suppressive) fire and try to cover if they can before shoot back. Even with 75 bullets from the MG-34 you can force an enemy to get his head down during few seconds.
In RO2, one or two will run or take cover, the others will just blow your head with a clean head shot (and they are your target, not soldiers who are around).
Just to say that in find frustrating to get head shot, clean and straight, by my target when i play the MG class. Yes you are a good player and do super MG shot and are happy.
But not all players are super-pro gamer and the average player find the rifle easier to kill someone, including the others MG.
Just look the slots, they are often free, that's speak for itself.
Note: In RO/DH i never seen this. Free slots like that...
But I'm -not- a good player. I struggle to hit enemies at all ranges, and if it weren't for team points I used to hover near the bottom of the scoreboard. Then I discovered that the LMG worked perfectly for my style of play (stalking around the flanks picking off unwitting dopes). I'm still not a great shot, but the LMG lets me compensate for that through fire saturation. I've never been in a situation where I've opened up on a group of 3-4 guys and had one of them turn around and shoot me. If any of them stop and turn, I prioritize them first, then their buddies that are running to cover. I'm -always- firing from a prone position behind an embankment, or near the bottom corner of a low wall, or through a hole in the scenery. The only real skill I have is the ability to identify terrain that will make me very hard to spot. The rest of it is just basic FPS marksmanship.
That's not to say that the LMG doesn't have a SIGNIFICANT learning curve, and most people don't want to wrestle with it. Just give us time, you'll start to see some awesome dedicated machine gunners within the next few weeks.
Long story short, the LMG is basically a huge, fully automatic -rifle-, and should be used as such. Pinpoint firepower used to headshot anybody dumb enough to try to get into a stand-up fight with you. You're more than accurate enough to prioritize targets, so if you see anyone stop on their way to cover, you swing your barrel around and let them have it. PUNISH THEM for their impudence, thinking that they could dare to stand before you. You are the lord of the battlefield! Dominate it as such!