First, to quote the inimitable Jong:
Also, holy pallies are shooting lazers out of their hands.
On the first night of raiding post-patch we went to Icecrown Citadel. I tried using Light of Dawn, but I just wasn't impressed by it. It didn't seem to do anything, and was always on cooldown.
But then last night, we went to Ulduar. And I fell in love with the spell.
The thing is that raid damage is fundamentally different in ICC than it was in Ulduar. In ICC, raid damage is constant and heavy. Aura damage fights and many random sources of damage abound. In this environment, Light of Dawn seems exceedingly feeble, and the long cooldown just makes it pointless.
But in Ulduar, raid damage generally follows a pattern. The boss does a special move and the entire raid takes damage. The raid damage is not constant. In this environment, Light of Dawn shines. XT has a tantrum; all the paladins bust out Light of Dawn in response.
And that interaction is just incredibly fun to me. Perhaps it was because those points used to be the worst part of healing for a paladin. Sure, once in a while you could use Aura Mastery or Divine Sacrifice, but most of the time you were frantically single-targeting the people with the lowest health, cursing your lack of tools.
The best analogy I could come with was back when I played Magic: the Gathering.
Opponent: I Fireball you for 7,000,000 damage.
Light of Dawn feels like our counterspell:
Raid Boss: Ha, ha. Eat my super-move of mega raid damage.
Holy Paladin: Light of Dawn.
Obviously, it's not a complete panacea, you still have to heal everyone up. But it feels fun when I use Light of Dawn in Ulduar.
It even makes the choice of glyphing Light of Dawn more obvious. Does the move you want to counter occur every 20-30 seconds? If yes, glyph Light of Dawn. If it occurs every 30+ seconds, glyph something else.
Now, we don't really know what raid damage in Cataclysm will be like. Hopefully it will be more like Ulduar than ICC.