Why does no one suggest flameglow? If you do the math, it often reduces the same amount of damage you heal/reduce during temp shield(even assuming it does not get dispelled, too) and has the added bonus of also reducing damage the entire game.
Highly consider using it vs hunters, dks, locks, rogues, enh shammans. For every roughly ~5-6k attack you reduce 1000 of it. For higher attacks, up to 2000, and works for every attack. When you die to a team, check your combat log and see if from the start of dying to the point you died if flameglow would not have done better to keep you alive. You fill find very often vs rogues, locks, dks, hunters, enh shammans it would have,
Flameglow used to be pretty good a few patches ago but due to the changes to this tier you cant really compare them, temp shield is alot better. If you only look at the damage reduction temporal is much better at resisting burst, and as you know this game is all about burst.
Also take into consideration that temporal can be used at your own choosing, it obviously has a higher skill cap and the reward is alot higher than Flameglow can ever provide. If you then add the healing that temporal offers it's clear that temp shield is the winner, no doubt about that.