Light of Dawn is fun, but tricky
I believe that at some point I deluded myself into thinking that Light of Dawn is more powerful than it actually is. While the ability seems like fun, it's simply not powerful enough to keep up any targets through serious damage. In addition, raiders aren't used to stacking up anymore. There are so many negative effects to stacking that nearly every raider tries to create separation between himself and others. I tried searching for the right place from which to use LoD, peeking around like a photographer trying to find the angle for the perfect shot. Unfortunately, that moment never really came. Luckily for us, LoD healing is replicated through our Beacon of Light, which means that using it will actually transfer quite a bit of healing to the currently Beaconed target.
Raiders are going to need some more training before I'm going to pull off any great Light of Dawns. I have hopes that I'll be able to coordinate my raid well enough to find situations where we can purposefully drop AoE heals in one place to facilitate quick group healing. Otherwise, Light of Dawn is going to fall victim to Lightwell Syndrome -- a great heal that requires the rest of your raid to act in order for it to work properly. With the buffs to the AoE healing of the other classes, I'd say you're better off using LoD sparingly.
Divine Light is too slow
Don't blame Divine Light for how weak it is right now. Divine Light is intended to be a slow heal; that's the entire concept of the spell. Unfortunately for us, we're not playing under the new healing rules of Cataclysm in which tanks can survive multiple blows. Healing in Icecrown Citadel is so incredibly fast-paced that we're not able to wait for a Divine Light to arrive. Even paladins with over 1,000 haste rating are having the same issue with DL, and there's really no fix coming until Cataclysm is released.
There's no need to fret over Divine Light; we'll be using it in just a few short weeks. Blizzard even left us a surprise to carry us through the last ICC raids we'll participate in. Flash of Light, while intended to drain your mana quickly at level 85, is still pretty castable at level 80. If you're being smart about your mana, you can easily use a mix of instant heals and Flash of Light to tackle ICC bosses, especially on heroic modes. It's a quick heal that does a significant amount of healing, and our current mana pools are sufficient to keep casting FoL for an entire encounter. For example, FoL is the heal that we're spamming on Valithria to top her off as quickly as we can -- well, that and the newly bugged Lay on Hands, which has been healing for six digits on a regular basis.
Skipping triage saves lives
In the time it takes you to read this sentence, five people in your raid group are going to die. Incoming damage is at its highest point ever in ICC encounters, and we simply don't have any time for deciding what spell to use. Holy Shock is easy enough to use, but then what's the next spell we cast? We could wait and see if the HS crits and then utilize Infusion of Light, but what if it doesn't? Should we then use Word of Glory -- but how many holy power stacks do we have? How much more damage is that target going to take? Can we spare the mana to use Flash of Light?
We're not typically in a position to spend even a moment figuring out what our next spell should be. If the tank is getting slammed, he needs powerful heals consistently, and we will end up either spamming one heal or migrating towards a fixed Tower of Radiance rotation. When the raid is on fire, we have to have our next heal already in the queue if we hope for it to get there in time. Blizzard's team has stated that the larger life pools in Cataclysm should lend themselves to a slower pace of healing that will allow us to dole out healing in a more regulated manner. Whether or not that is true remains to be seen, though I can attest to the massively inflated HP values I've been seeing on the beta.
I suggest forgetting about playing perfectly and focusing on keeping people alive. Use Holy Shock and Word of Glory as tools to get heals to people instantly, but don't freak out if you cap out on holy power or use a two-point WoG. Worry about getting your targets healed quickly and you'll have completed your duties. Cataclysm brings a lot of new variables to the healing game, and until those are introduced, it's our job to do the best we can with the tools that we have.
The Light and How to Swing It (Holy Edition) helps holy paladins become the powerful healers we're destined to be. Learn the ropes in Holy 101. We can help you keep a tank alive, heal a raid when necessary and beat the global cooldown. Tanking is a job, DPS is a craft -- but healing is truly an art.