Actually incorrect. Writhe in Agony is going to pull ahead of Effigy in Single Target and Cleave. Haunt is going to be useless because it costs a soul shard that i would rather use on a spell that actually scales with our artifact traits, Reap Souls, and Mastery so it doesn't even outburst Unstable Affliction. As far as the actual damage buff to Haunt goes, Writhe in Agony with Effigy will outclass it and doesn't cost extra shards.