Testament of Arathor

The waves of incoming adds (~4-5 mobs each wave) will be a random mix of the following:

Dark Rune Commoner (~9k HP in 10 man, ~25k HP in 25 man)
Melee for ~500 in both 10 and 25 man.
Use Low Blow - which hits a melee-range target for physical damage ( ~150-200 in both 10 and 25 man), and reduces the damage done by the target by 3% for 20 seconds.
Use Pummel - which hits a melee-range target for a negligible amount of physical damage (<20 in both 10 and 25 man), and interrupts the targets' spell casts for 5 seconds.

Dark Rune Evoker (~33k HP in 10 man, ~160k HP in 25 man)
Melee for ~2k in 10 man, ~4k in 25 man (they generally only melee when out of mana; they should die before they run out of mana).
Cast Runic Lightning - a 1.5 second cast, this hits a raid member with nature damage (~6-7k in 10 man, ~9-10k in 25 man). This can be interrupted.
Cast Runic Mending - a 2 second cast on an ally that is both a direct heal (for ~8k) and HoT (3k per tick for 15 seconds) similar to a Druid's Regrowth. This can and should be interrupted. If it lands, it can be dispelled from the mob it hit.
Casts Runic Shield - a 0.5 second cast self-buff that absorbs 40k magical damage, and reduces all physical damage taken by 50%. This can and should be dispelled.

Dark Rune Warbringer (~34k HP in 10 man, ~190k HP in 25 man)
Note: this mob can be Mind Controlled, and doing so will let you give the Aura of Celerity to your raid. Killing Thorim with this Aura active is an achievement, and the Warbringer itself does a great amount of damage to Thorim. If you have a someone who can MC well, have them do it. It's not necessary, but it's a great help. If they are worried about being able to hold the MC long enough, it's also possible to just CC the Warbringer until close to the end of the fight, then Mind Control him and get the Aura for the last few percent.
Melee swings for ~1-2k in 10 man, ~4-5k in 25 man.
Use Runic Strike - which hits current target with nature damage (~5-6k in 10 man, ~11-12k in 25 man).
Grants Aura of Celerity - which buffs all allies within 40 yards, increasing melee/ranged/casting attack speed by 20%.

Dark Rune Champion (~54k in 10 man, ~200k in 25 man)
Note: these are Vyrkul models, the rest are Dwarves; this may help tanks and Disarm-ers pick them out faster.
Melee swings for ~2-3k in 10 man, ~4-5k in 25 man.
Uses Charge - a 8-25 yard range ability that stuns the target for 2 seconds and does physical damage (~8-9k in 10 man, ~14-15k in 25 man).
Uses Whirlwind -the Dark Rune Champion whirls around, hitting targets in melee range for physical damage (~2-3k in 10 man, ~7-8k in 25 man).
Uses Mortal Strike - hitting the target for physical damage (~8-9k in 10 man, ~13-14k in 25 man) and reducing healing taken by the target by 50% for 5 seconds.

Have healers try to stand on opposite sides around the edges of the raid group (to keep from all being hit by the same Deafening Thunder, and a bit out of the main clump, but still close enough to the middle to avoid being hit by the Lightning Shock from a Charged Orb. As much as possible, have them stay out of melee range from the Dark Rune Commoners to avoid being hit with Pummel.

Have tanks pick up as many of the mobs as possible, giving priority to keeping any Dark Rune Warbringers and Dark Rune Champions under control. DPS should use AoE as much as is feasible, but make sure to focus fire down any Dark Rune Evokers as a priority, and make sure someone gets on the Dark Rune Evokers to interrupt their casts. Additionally, having someone ready to Disarm any Dark Rune Champions immediately after they spawn can help smooth out the damage in this phase. Anyone with a means of dispelling should use it on the Dark Rune Evokers to remove their Runic Shields and any Runic Mending that doesn't get interrupted in time.

Because of the effects of Thorim's Stormhammer and the resulting Deafening Thunder, it's useful to have healers with lots of HoTs and instant heals/shields. This half of the raid will take quite a bit more damage than the hallway half, so divide healers accordingly.

Just stay in the middle, and react to each set of mobs as quickly and cleanly as possible to keep up with the pace of the waves. A new wave will come approximately every 30 seconds, and will be a random mix of the above mob types.

Tanks, DPS players, and healers will all need to be on their toes at all times, and know what to do with each mob type to keep things under control.

Also regarding Unbalancing strike. I've just read what the spell does, and if i'm correct tanking him with a druid would solve the problem of taunting? I might be wrong here so correct me if i am