I also thought of the wth is the point of playing the other classes... but then i realized this.

Champions - excel in melee and ballistic combat
Commando - excel in ballistic combat
Berserker - excel in melee combat
Defender - excel in defensive abilities
Bio Engineer - excel in supportive abilities

Well, if i roll a commando, im going to suck in melee, and if i roll a berserker Garm is going to be 1 hell fo a bitch, so i will roll my dps, tank, and healer. I think the berserker and commando classes are for die-hard fans of the spec. those who love to do melee or ballistic