If you're a holy paladin with a pulse, there's no reason not to be raiding Dragon Soul. The Raid Finder allows us healers to find groups in minutes, with no strings attached if you have to leave early. The normal versions of the bosses are all accessible for guilds across the spectrum of dedication levels. Healing a raid in Dragon Soul gives you access to the best gear available and provides us with the greatest challenge we can face today.
I was looking at my World of Logs parses from the old days, and I was surprised to see how bad my HPS looked then when compared to more recent parses. The first step in preparing yourself to heal in Dragon Soul is to realize that the instance isn't built like Bastion of Twilight or Firelands. While the Ascendant Council repeatedly punished the raid for clumping and Baleroc crushed our tanks, many fights in Dragon Soul involve tight stacking and tons of AoE healing. Optimizing our AoE healing has become a key to succeeding in Dragon Soul.