We all know that Renew does what a Disc Priest just does in that it softens the impact that a tank's health bar is gonna drop. Renew works wonders for this, it's true, but in the same amount of time, you could do a flash heal that heals roughly the same amount, for the same amount of mana, causes rapture, can crit, causes Aegis, blah blah blah.
Anyways, after looking at Glyph of Starfall, and the Shadow talent, Pain and Misery, here's me thinking, what about a Glyph of Penance?
"Your Penance heals refresh the duration of your Renew on the target"
Would that not fix our little problem, and make it not just usable but even desirable?