I agree, also some of the combinations of abilities that can pull things out of a rough spot... for instance a Disc Priest with glyphed pw:s can drop PW:S for mitigation and a light heal, gain Borrowed Time, activate Inner Fire and pop off a guaranteed crit Greater Heal with the extra Borrowed Time haste, with +4% from Renewed Hope, which is usually over 14k for a Naxx-10 Disc Priest... plus the target is left with Grace for a followup heal (or HoT), and a Divine Aegis shield (and possibly an armor boost from points in Inspiration). That will take a tank from 'uh-oh' range to 'you hit like my grandma!' range, and leaves the tank with some massive mitigation (30% of 14k is ~4.6k, plus any remaining absorption from pw:s, plus a 3% reduction from Renewed Hope, and any additional armor from Inspiration..)

Sure there are CDs to use, but figuring out how to best mix your GCD spells for the necessary effect is also key. It would be nice to see a breakdown of common techniques and spell syngeries for the healing-capable classes.

He's talking about abilities that are different from the normal "toss out a big heal when the tank takes a lot of damage" mechanic. These are all abilities that either lower incoming damage or increase health beyond its normal maximum. The only exception to this that was mentioned was divine hymn, which is definitely awesome enough to warrant its inclusion. Swiftmend, while very powerful, is simply a big heal. I'm not sure why Barkskin wasn't mentioned, though.