The automatic rifleman is a relic from a time when the game only had 1 loadout per class, so the auto rifleman was used to give out Bars and Stgs.
Now the class is basically "I want to use STG" or the "Assault is taken".
At its core it is the same as assault, high DPS class meant for offensives.
The class has also translated horribly to new factions whom didn't have automatic rifles, for the Soviets the automatic rifleman is literally just a second assault class and for the Germans it becomes obsolete after reaching assault 9.
And with the possible introduction of weaponry becoming accurate year to year, balancing the class will become even more difficult. Many countries lacked a arsenal of automatic small arms of any kind at the start of the war.
AR is a useless class. It provides marginal benefit in killing power (which is negated by the ease of shooting and the Low TTK of other weapons) in exchange for situationally useless loadouts. The only exception being the smokes on the second loadout but even there are better classes to choose for this function.