This came abruptly to an end when the autocannon made it in to the game. Suddenly you didnt have to fight the other dropsuit classes on their own terms with weapons ill-suited to the heavys slower movement. Now you could outlast any other class in a head-on firefight (though smart players can still outmaneuver the slower heavies), you had more armor and a lot more firepower; enough to destroy light vehicles as well as infantry.
Find out more about the other DUST 514 weapons of war in the full developer blog.
Source: DUST 514 website