To be clear, I'm not suggesting these auras as a DD buff, instead they should present different possibilities that aren't currently available.
Spraying spells is one of the more engaging ways to play nod but it's a horrible experience pre-cap due to deft recovery driving most of the dps, and how hard mana/stat management is without great skills. The blue aura aims to help with this.
Red Dcdd or red/green staff dd does great in pve and people have done well with that in PvP too. It's the other colours that present an opportunity for a bunch of variety in other builds, either as supplimentation for non strictly casting builds or entity different types of debuffing casters we don't currently have.