Rain of Fire isn't like Rushing Jade Wind, the only spell I can think of off the top of my head that is used at times in Single Target situations where it was designed for AoE, RoF has a targeting reticle which makes it significantly more annoying to have to use constantly throughout a fight and costs an absurd amount of mana as well (the latter is probably due to the fact that it is meant to be used with FnB).