Unfortunately for us, there are other classes in the game. Holy specs have been dominating, and giving paladins a serious boost in potency is not a good way to ensure that druids and shamans aren't getting benched. We're not the only healing class, and we're not being balanced in a vacuum. We need to have the same relative strength as our colleagues. While a 9% differential may be okay in the long run, holy paladins were already in the lead. Blizzard's devs obviously want to solve problems and fix bugs, but holy paladins were already balanced around Conviction being broken.
Theoretical performance is important, but it simply can't replace real-world testing and numbers. We were designed around Conviction working, but the empirical values that were being collected were faulty. At the end of the day, holy paladins need to be relatively balanced when compared to the other healers. Even with the nerf to Walk in the Light, we still end up with a net gain to our overall healing from the Conviction change. It's a buff -- it's just not as large as we would've liked to have seen. Can we really complain when our already potent class becomes even stronger?
Buff our mana, nerf our mana
After all of the Conviction/WitL changes are said and done, we'll see a 4% buff to our healing throughput. Divine Plea is also being buffed on the PTR, and in two separate ways. Its duration is being cut to a mere 9 seconds, meaning our healing is subjected to the Mortal Strike effect less of the time. In addition, it now restores 12% mana instead of 10% mana. The glyph was buffed too, increasing the final mana amount to 18%, versus the 15% of the past. It's a buff to our overall mana and healing, which is always a good thing.
Remember what happens when our already-potent class gets buffed? A nerf comes in to ensure that we remain balanced. All three of our single-target cast-time heals had their mana costs increased by 10%, resulting in a hit to our efficiency. It's not a 10% loss, since many of our spells are unaffected by this change, but it still hurts. When balanced against the Conviction buff and the Divine Plea improvements, we're probably going to end up about where we started. Our heals are going to hit a bit harder, while our mana pool is simply a bit smaller. In the end, it's a push.
I really don't see the changes as being that severe, and my experience on the PTR reflects that as well. Do you always Divine Plea on cooldown? I usually only activate DP maybe once or twice a fight, and so I know that simply using it more will offset the increased mana cost of a few of our spells. It's rare that you're actually stretching your mana as far as it can actually go, and so this change simply means we need to be more disciplined -- but only a bit. A mana potion or a few extra Seal of Insight procs will offset the change easily, and so it's only the careless who will be feeling any pain.
Beware of the healing meters
It's easy to look at the news reports of the Lady Sinestra kills and assume that holy paladins are the best healers in the game simply because they're located at the top of the healing meters. The truth is that WoW has to be balanced at many levels, from regular dungeons to the world's most difficult heroic raid encounters. Superguilds like <Paragon> or <Method> push mechanics to their limits in order to be the first to achieve truly impressive feats, but their positions are truly unique. The vast majority of holy paladins will never get to be in these situations. While their experiences are valuable, the limits of balance can break at the bleeding edge of progression.
The reverse is also true. For most raids that are working on normal mode encounters, class balance is rarely the limiting factor in how well holy paladins perform. Learning to play your holy paladin more efficiently and more effectively is nearly always going to result in a bigger difference than a simple buff of nerf. Your fellow raiders' learning to avoid fire and lava is going to affect the difficulty of healing an encounter far more than fixing the Conviction bug will. You would have to be playing your paladin perfectly and at the exact limit of its potency for the mana cost nerf to really impact your gameplay. How many of us end every encounter with zero mana? I actually don't mind nerfs like these, as they give me a chance to challenge myself to find ways to compensate. Nerfs can be an opportunity to improve your play, while buffs simply do the work for you.
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.