I've been taking a look at a few simlulation DPS charts and I don't see Hand of Light anywhere. Currently Hand of Light is my top 2 most damaging contributing ability only behind Templar's Verdict.
Reading the Mastery tooltip, Hand of Light increases the Holy Damage of most of our melee abilities by 34% + any additional mastery. Could it be that Hand of Light isn't being taking into consideration on those charts?