That whats an mg is made for, dude - crowd control! And I hope you think too, that moving a blob is a no brainer and should be punished. Mgs should always have to be flanked by infantry.
Game is designed to outplay enemy, therefore cant't see a useful comment in your reply.
And an MG will control like.. 2x it's manpower at least. More if supported but penal are 300mp and a blob of them is at least 900mp don't expect a 260mp MG to hold the line alone. If you can spot for it things will go well but not alone it won't.