Being bored in between class is usually when I conjure up most of my ability/talent designs. I was thinking of Auras and Aura mastery, and thought of this.
Empower Aura: Learned at level 15. Envokes the power of the Light to sanction your current aura. Refer to individual Auras for Empowerment effect. 1 min cooldown.
Devotion Aura: Increased Armor by X. When Empowered, you absorb up to Y
Physical damage equal for 10 seconds.
The idea here is that you can negate Physical damage (not based on your Armor type), without it becoming too powerful to be used as a Tanking cooldown.
Retribution Aura: Causes X damage every 4 seconds to all nearby enemies within 5 yards
while in combat. When Empowered, instantly deals damage equal to 20
seconds of Retribution Aura to all enemies in 10 yards.
Instead of being based off of being hit, it now pulses like the Shaman’s totem- The empowerment works like an “all target” Holy Wrath without the stun component. This would be subject to the AE target cap in 4.0. Should also note that the aura itself will NOT generate aggro, but when Empowered, it WILL generate aggro.
Concentration Aura: Lose 35% less casting or channeling time when damaged. When
Empowered, your next spell cast within 10 seconds has its cast time reduced
This one was tricky, because I still want Aura Mastery to be useful; Thus, making it reduce the cast time instead of granting silence/interrupt was the way to go. If not cast time, maybe Mana cost instead (although that doesn't really fit)?
Resistance Auras: Increases Magical resistance of aura by X. When Empowered, you
absorb up to Y Magical damage for 10 seconds.
Functions the same as Empowered Devotion, except with Magical damage based on your current aura.
Crusader Aura: Increases Mounted movement speed by 20%. When Empowered, you
move 20% faster for 15 seconds.
Useful for PvP, or getting back to your target quickly. If too powerful, maybe make it non-cumulative with Hand of Freedom. It should stack with PoJ, though.
Now, this is just a rough idea. Maybe each tree can have a talent that improve certain empowerments (i.e. a talent in Ret that allows Empower Aura's cooldown to be reduced by 30 seconds if used to empower Crusader Aura, etc).