We're pretty speedy
Holy paladins have always been fast on their feet, especially considering that nearly every PVP talent build picks up Pursuit of Justice. Resto druids have Travel Form and Dash to get away from trouble, while shaman can transform into a Ghost Wolf to evade capture. Speed of Light was designed to give holy paladins a similar ability, granting us a speed boost when using Holy Radiance. The only issue is that Holy Radiance is very expensive, especially when considering you won't be healing more than a handful of targets with it.
The post-4.2 version of Speed of Light cuts the CD on Holy Radiance by an extra 10 seconds, making the speed boost available more often. More importantly, Divine Protection now also boosts our speed when used. Many holy paladins pick up Paragon of Virtue for PVP, which makes Divine Protection available every 40 seconds. We are faced with an important decision when using Divine Protection, though, as it is one of our defensive cooldowns. It makes sense that when we use DP for defensive purposes, we're also granted a speed bonus, but using it for the speed bonus alone means that it might not be available when we need it later.
Another instant heal
Speaking of our mobility, patch 4.2 brought another key change for holy paladins on the move. Infusion of Light now also reduces the cast time of Flash of Light by 1.5 seconds, which makes it an instant-cast. Flash of Light is one of our bigger heals and a PVP staple for when we actually had to cast, but obviously making it instant is even better. Infusion of Light is activated by Holy Shock critical effects, which we see plenty of on a regular basis. We can even hold the Infusion of Light buff for up to 15 seconds, waiting until we absolutely need the Flash of Light. Our toolbox of instant-cast heals is growing quite large, which is important for preventing our holy tree from being locked down.
Beacon gets a boost
Beacon of Light can no longer be dispelled, answering the prayers of holy paladins everywhere. The Beacon of Light major glyph might no longer be mandatory, as reapplying it for free was necessary to counter enemy dispellers. In addition to become undispellable, Beacon of Light now also transfers 100% of our Holy Lights, as opposed to the old 50% transfer. I think this change was largely aimed at PVE raiders, as it makes Holy Light a valuable tool for raid healing. I rarely get the time to cast a Holy Light in PVP, and usually it's a waste of a cast anyway. I can see how it would be useful in small-scale fights where you might have time to get a cast off, but I don't see this getting much use in anything outside of 2v2 arenas, where you can be more creative.
Our primary PVP healing spell, Holy Shock, had its mana cost cut to 7% of our base mana, a reduction of 12.5% of the spell's original cost. Considering that we use it on cooldown, this should save us quite a bit of mana over time. The downside is that the cost of all of our casted heals went up, although again we're not casting too many spells. Holy paladins try to rely on instant-casts as often as we can, casting a heal means opening ourselves up to getting interrupted. The Flash of Light mana cost increase will probably hit us the hardest, especially considering we'll have it available more often with the changes to IoL.
Light of Dawn gets discarded
Many holy paladins skip our 31-point talent, Light of Dawn, when choosing their builds. It's not very effective in the arena or battleground, and we have plenty of other attractive talent options to choose from. Word of Glory is a better way to spend our holy power points, and so Light of Dawn was never really that great. Our Walk in the Light tree bonus was recently buffed to increase our WoG healing by 30%, putting the nail in Light of Dawn's coffin. Nobody is going to pick up LoD for PVP, as you're wasting holy power points that could've gone to Word of Glory. Word of Glory was already great for PVP healers, and now it's even better. Not only are we picking up new instant heals, but both Holy Shock and WoG were buffed as well.
Shockadin DPS is pretty bad. I recently quested my way through the new Hyjal quest series with my shockadin build, and it took forever. I was on the third elemental stage when a mage in my guild started the chain, and she caught up to me before I was even finished with the third stage. Denounce makes Exorcism affordable to spam, but Exorcism simply doesn't have enough supporting talents to make it worthwhile. Denounce used to occasionally give us a free/instant Exorcism after using Holy Shock, but it wasn't really worth the GCD to use Exorcism since it did so little damage.
The new Denounce was designed specifically with PVP in mind. After we use Exorcism on someone, they can't score any critical effects for 6 seconds. The debuff works on both damage and healing abilities. While I like the idea here, the fact remains that Exorcism is based in our holy tree. If we get interrupted while casting it, we're locked out of all of our spells. We won't get any more instant Exos since Denounce was redesigned, so we're stuck hard casting every single one.
I can see it being useful if we get the opportunity to use it on someone trying to burst down one of our friends, but we'll just have to be very careful. If we get interrupted while they're already attacking our ally, then our teammate is even more likely to die. I do like the fact that holy paladins now have a completely unique bit of utility, as I am sure we'll be able to come up with some creative uses for it eventually.
The Light and How to Swing It: Holy helps holy paladins become the powerful healers we're destined to be. Learn the ropes in Cataclysm 101 for holy paladins, study the new balance between intellect and spirit and learn how to level your new Sunwalker. Tanking is a job, DPS is a craft -- but healing is truly an art.