I must somewhat concur. As I play mainly medic in all Battlefields, I was a bit baffled by this choice at first (although it has a logic on a paper), but when they announced it is a class weapon so it won't have some penalties, I said myself - why not? It can be actually fun!
I really tried to like it, but as I prefer to be close to where the fight is, so I can quickly react and keep teammates up, the incredibly slow ADS of LMGs entirely killed any appeal, for this role. I can imagine using them in some defensive scenarios where revives aren't that much needed, but otherwise - nah, I will use ARs or SMGs instead. But maybe there will be lighter machineguns without the harsh ADS penalty present on the release and I will give them a chance again.