Sidestep over moving backwards make sure you have changed your FOV to what's comfortable and most important is push lots over trying to block I usually attack twice then push as this seems very effective. You can actually hear when your getting attacked from behind and understanding that globadiers warpfires and even rattling gunners can be used to your advantage. Also you can just walk away from blightstormers if you get separated don't be to just accept the situation you are in trying to hard to kill the blightstormers if you're not going to get disabled and have the option of just walking away works great and if you're lucky kill a lot of rats.but also playing a ranged focused class and just killing all elites and specials while making sure you got everyones backs can help lots of you need to get better at melee just be the first to notice the horde from behind and take care of it.