The answer to your lack of understanding of the problem is contained within your own sentence - there is no way a frontal assault by frontline infantry should hard counter a machine gun. The whole point of machine guns is to hold back infantry that walks into its arc of fire.
the idea i think is that you are suppose to support your mgs they arne't suppsoe to be able to be effective on there own.
the replays aren't compatible as you need the game to run them reason is that it uses the game to recreate the commands. (also why when a patch showsup they are obsolete.)
now you can watch a caster or uploaded avi file such as RnP, and ATR cast. and from youtube or whatever video site.
the problem i find is the maxim squads for some reaons love to bunch up in one big group making them easy picking for a nade... when/if they fix that i think it will be fine but onyl then do i think you can really establish a postion.