Swarm missiles in their current state make Ranged builds designed to poke away at the opponent from distance completely irrelevant.
They seem to have a large AoE Explosion that deals full missile damage, they reload relatively fast.
fire off SEVERAL missiles that do extremely good damage in comparison to other missiles that fire off 1 to 2 at a time.
The Missile Swarms have outstanding accuracy over distance.
Forces the opponent into close range unless they want to actively deal with the missile swarms and how hard they are to avoid making long range and speedier builds irrelevant.
A good missile swarm can easily out damage all current ranged weapon with how accurate they are.
In a straight up fight between a Light Weight and a Heavy Weight build using Swarm Missiles the Heavy Weight easily wins.