1. Inferno is used for a raid that doesn't require a counter skill. Change Squall skill 2. Seraphic hail does not use Because you get less identity than using Esoteric Reaction and Rime Arrow
Igniter sorc is the best class in Dameage, but it requires a little control and proficiency. So it might be difficult for the first time. i think you start Specialization, Swiftness igniter sorc and when you master it, change to Swift as Crit stats