So I finished my Daka +2 finally and got a chance to play around with Rudra's Storm.
Outside of abyssea, it's pretty meh, but it seems to do better on higher def mobs than DE/Evisc does on average.
Inside abyssea, it's still pretty meh, does about the same damage a fullhit DE would pre-atma. (about 1kish)
But! There's still something it's useful for.
If you were like me and never got Pyrrhic Kleos, Rudra's Storm can open Darkness. ALSO, it can Double Darkness since it's element is Darkness itself. (which is something PK can't do by itself.)
So far my highest self SC damage in Abyssea was for 7.7kish vs Gnawtooth Gary.
1406 Rudra's Storm> 2994 Evisceration> 3312Darkness.
It's a nice toy after all, I was originally just getting it as a trophy. The Higher base damage pushes my average evisceration damage up by about 200~300.