having suppression teams deal high damage while suppressing works perfectly fine; look at dow2. everything is more lethal in that game.
Well, to be fair, that's probably because DoW2
also had melee assault teams that could literally jump into said suppression teams regardless of those suppression teams' power and then probably wreck the suppression teams super hard because retreating causes units to take more melee damage. Also, I recall a fair amount of players voiced discontent with that latter part so, you know...nuthin's perfect.
My guess behind the HMGs'
very heavy reliance on being supported in CoH2 is meant to balance out how a unit they suppress will stay suppressed as long as pretty much anything is shooting at it, unlike in CoH1 or DoW2 where after the suppression source leaves, suppressed squads will recover pretty quickly.