For a Pure Bomber, in what aspect does Ash of Agni shine? It just seems that whatever Ash of Agni can do, there's another bomb that can do better. In terms of ranged damage, Dark Retribution seems to do a better job. AoA's damage just seems too slow for me. In terms of support, the damage it provides seems to pale in comparison to the utility of the other support bombs like Voltaic, Stagger, and Shiver (since if I'm playing support, my teammates already assumed the DPS roles).
In which situations does Ash of Agni do a better job that other bombs can't?
Ice Cubes. You can also stack an AoA with a VT since putting down two VTs in a row isn't going to shock the enemies even more.