*will update with your smart ideas and talent/glyph recommendations*
The Stone Guard
Bladestorm - Situational use in popping a chain cobalt mines, if freedom abilities from other classes are at a premium. If this isn't needed, Avatar seems the most helpful as the enrage timer (if it exists) is not challenging on any difficulty.
Vigilance - As safeguard cannot be used on the second tank, this doubles up as an extra cooldown for them. The unlimited taunts are less useful because you must have cast it before taunting, otherwise it will not take effect until taunt comes off cooldown. This would require you to know in advance that you are going to mess it up.
Feng the Accursed
Safeguard - Given the frequency of tank swaps, having this available each time the other tank takes over is useful.
Shockwave - Useful for stunning the shadow minions spawned by the shield.
Dragon Roar - If stuns and snares are plentiful in your setup, you should be able to utilise Dragon Roar on each spawn of shadow minions.
Gara'jal the Spiritbinder
Safeguard - You can intervene shadow attacks, when you are not tanking, and use this on three occasions (pre-banishment, emergence, and before the other tank is banished) per tanking round.
Dragon Roar+BB can be used at the start of your tank round, and again to effectively one-shot one of your severer's, reducing the need for your DPS to help you.
The Spirit Kings
You can get some decent mileage out of Shockwave and Stormbolt for dealing with Subetai's Slight of Hand ability. You can keep him stunned for the full duration (until pillage) with both. You can also interrupt pillage completely with a stun (use the ability as pillage comes off cooldown).
Vigilance is reasonably useful for protecting people hit by pinning arrow, though other classes have much better tools for dealing with that than we do.
Use Dragon Roar with Bloodbath for burst on the adds between phases (Group them all up with Mocking Banner for AoE/Control). Glyph of Heroic Leap is also handy, as on whichever crystal wave your group struggles with the most you can utilise a Bloodbath'ed Leap and Dragon Roar to hit all three crystals on one side and knock off a good third of the HP, plus the followup damage from the bleed.
Will of the Emperor
Piercing Howl, to drop a slow on Courage's which spawn on my side, but this is temporary and very situational. Vigilance is handy to allow certain classes to soak Titan Sparks if they have weaker personal cooldowns.
Avatar is useful if a Courage actually reaches you.
Glyph of Leap and Enraged Speed are semi-useful, for dodging devastating arcs if you have trouble with that.
Heart of Fear
Imperial Vizier Zor'lok
Blade Lord Ta'yak
Wind Lord Mel'jarak
Grand Empress Shek'zeer
Terrace of Endless Spring
Protectors of the Endless
Sha of Fear