I'd like to see those replays for myself, I just tested my own feelings by going into CheatCommands mod to see it and it worked like I expected - max range, target out of cover, always suppresses with the second burst. I actually saw it suppress once on the first burst to my surprise since I had the sense before HMG34s really couldn't no matter the range they were firing at.
Ah, people usually call them bunkers.
The issue with the MG34 is that it's fine because it's cheap in a faction with a lot of MP, but that's it. It has nothing special about it, the 1-3 veteran abilities are literally copy pasted from the MG42. And it's extremely low survivability makes getting to those levels extremely hard.
The maxim is unique in that it has a 6 man crew, and does reliable suppression to one squad and with a bit of micro can even take on largish blobs. It also gets a bonus to being in buildings.
The .50 cal does the suppression of a MG42 while having a MUCH faster set up time, allowing to act as a good support weapon behind your rifle blob suppressing elite infantry so they can't kill your rifles.
The MG34, much like the Dshk, is just a piece of shit because it's a copy of a unit. The Dhsk is more expensive but more fragile than the maxim, and the MG34 is cheaper than the 42 but has worse stats/the same stats in every category. If you want to raise the cost that's fine, but it should have it's own defined roll instead fulfilling the roll of a unit that already exists in the same faction alignment.