The goal of this build it to apply status, to kill after with the melee weapon with [Condition Overload].
For this, the [Phage] is one of the best choice, because it is one of the rare weapon that can apply Viral and Corrosive, it can hit multiple taguet in front of you, and have good status/second. (with this build, it apply 10 status per seconde)
(The other best is the [Kuva Nukor] : more status per secondes ; have an other mechanic to apply it on a lot of target, can apply 1 more status if the element is magnetic, but can not apply Viral+Corrosive. )

Scatering inferno is not at rank max, because we don't need lot of fire proc : more than 1 will not make more armor reduction or more damage from Condition Overload.

For a riven, the best attributes are :
-Punch through (if you have it, put instead of Seeing Force)
-Multishot
-Status duration
-Fire rate
-status chance