Hmm, I think it's easy to understand that I'd rather not see this card buffed.
Holy Light is one of the few hard counter cards, they're not very effective in many cases, but when they are, they are ridiculously overpowered and game changing. There is no single card that can deal as much CC damage as Holy Light and it's one of the cheapest cards as well.
I personally would like to see a buff accompanied with a nerf or removal of it's damage against Death/Darkness creatures (buff: let it heal them, too? :P). One curious buff would be for it to turn into damage upon reflection (nice indirect buff to Reflective/Mirror Shield, obviously implying it would be reflected).