Its actually very simple, a picture is worth a thousand words. The assault rifle does 2 times the damage of the plasma cannon. The assault is out damaged by every class that can equip an assault rifle. Practical testing backs this up. Using LemonKings DPS meter You can see the plasma cannon doesn't even come close to the AR in terms of damage. First are foremost, forget about splash damage. The radius is very tiny, players move very fast, and now they spend very little time on the ground. Splash is a nice bonus to the plasma cannon, but you have to be getting consistent direct hits to reach its full potential. The plasma cannon is a slow moving projectile with a slight arc, this makes it very hard to use compared to the fast moving AR rounds. The assault rifle is so much easier to use, and completely outshines the plasma cannon is every way. All the abilities are basically useless, lets just agree on that for a moment. That leaves the plasma cannon as the one defining trait of the class, yet that one trait is outmatched by something every single other class can equip. Splash damage mattered a bit more in the last build, but in the current one you have so few opportunities to take advantage of it that it cannot be considered a real trait.