My favourate potential solution is to just punish blobbing. The more of X you have in one area, the higher the accuracy penalty against them is. Make it so that rifle fire into blobs kills several people, or MG suppresses and tears into them. I hate that blobs can charge into machineguns and actually have a chance to win.
The logic of increased incoming accuracy is if 20 people are charging at you and you shoot back, even if you're a bad shot, you'll probably hit SOMEONE. It's so weird seeing an MG 42 or Maxim shoot into a large crowd of people and only kill a couple before being forced off.
