This is the kind of logic that makes tech startups go belly up.
This has nothing to do with player capability/skill. It's a UX design issue. You can't allow a feature to be designed in such a way that a slight twitch in an enemy unit's movement results in the complete collapse of a frontline because of a tearing down HMG squad.
Nor should an extremely vulnerable suppression arc weapon be chargeable head on by the very units it's supposed to hard counter.
But yes, keep blaming players for bad UX design. It's well in line with what Relic have been doing for ages (see Dawn of War II and how the Eldar Warlock's long range psyker AoE ability did nothing regardless of how accurately it was aimed and was never fixed).
You mix two different games and expect them to work the same. It's a design decision to make the MG turn slowly from their normal position. I think its a good one.
You rather have to see the MG as the 2nd half of the grenadier squad.
In german infantry you have 2 halfgroups in one group. You have the 1st which is the assault group and 2nd which is the covering group. 4 in one, 4 in the other, they work in tandem. If you sent one without the other, they arent nearly as strong.
This is how the MGs are portrayed in Coh2. If you leave an MG sitting alone, you are meant to be flanked, even from within the arc if they only sit in it for a second on the edge.
Use the HMG in their intended role without expecting them to rambo everything down.
For that you are a bit too late to the game. 6x maxim spam rolling through the country side is luckily a nightmare of the past.
Use HMG wisely and they are a nightmare for the opposition.
Also its a blatant lie that a squad can charge headone and not get suppressed. If 4 squads attack headon, thats "tactics" which worked before in warfare and why shouldnt 1000+ manpower not win over an MG?
In military doctrines to assault a position you are supposed to have a number advantage, but once you have that, you are good to go. I dont see a problem if 4+ squads charge an MG headon.
In diaries you can read all the time how the MG was indeed a great weapon, but it was also the most dangerous for the gunner, because all the firepower just centered on the MG. Rifleman, mortars, snipers etc. all focused down MGs. That's how its portrayed in CoH2. And its portrayed well.