During the Tron Council fight you can iceblock while targeted by Magmatrons fire beam-laser to avoid the ability. Just iceblock right when he targets you and cancel right after, he'll turn around without casting the huge flames at all, that deal massive amounts of damage to a single target and everyone in it's path, and continue to beat on your tank, hence saving you quite a lot of mana that would be used on keeping you and others up.

I don't know for sure if this qualifies as an exploit, but since it works on similar skills (like Cloak of Shadows) and hasn't been changed yet (as far as I'm aware) it's probably intended or rather "clever use of game mechanics".

Coming from Halfus wyrmbreaker 25 hc I have the following tip to share with you, this encounter can be done in multitude of ways but our raid decided to kill the time warden first, after which we released the whelps and slowly aoe'd them down. The way to abuse this as a mage was to shift your attention to Halfus sometime after the pack is released (instead of focusing on the other drakes like most of our dps was), hard cast pyro if you don't have hs, put up lb, blastwave the adds to proc impact, combustion and spread it to the adds.

Aka short version, impact combustion off of Halfus, at this point he's taking extra damage, with good combustion timing (after fireball crit) I've managed to get up to 18k combustion ticks going. Do note that this generates extreme threat, have mirror images or invisibility ready, after our kill and looking back at the WOL logs on my luckiest combustion attempt I did over 300k dps for the duration of the combustion. Said attempt didn't end in a kill but other mage did the same trick on the kill attempt and had over 200k dps going at the time of the spread, he ended the fight close to 60k dps.

Also on Halfus when he starts doing the stuns we had paladins and mages taking turns ice blocking/similar, cancelling it right after he casts third stun and then interrupt the shadow nova, this greatly increases raid dps and reduces healing needed.

Getting mindcontrolled on Cho'gall removes your dots on him, so wait with using combustion after he cast his MC.

I'm not positive if I was just lucky or not, but I found myself unstacked with the other ranged when I got a meteor on me in the Theralion phase of the two dragon fight, and I cast mirror image to save myself. Can anybody confirm if casting mirror image can distribute meteor damage?

On the Ascendant council fight, frost mages should park their water elemental right on top of the fire boss and the rest of melee. From that position, the water elemental will always get any damage buff that gets cast on a melee (whether it be fire or ice debuff). From their you will want to setup your UI to show which buff your pet has and have him attacking the correct boss with the buff.
When I started doing this I gained about 5,000 dps during that phase and a half a million damage from my water elemental alone.
This also works with Warlocks Imps and presumably and melee pet you could just have sit on the melee boss unless he get the ice damage debuff.

Also on the ascendant council, do not use Mirror images at the pull. Take it easy on dps and regulate your threat for the first 10 seconds of the fight. I have found that mirror images is absolutely NEEDED for phase 3 when the monstrosity comes out, and it is great to have for when phase 2 starts as all your cooldowns should be up and you can start burning without threat issues.

Post removed due to hotfix applied January 4th. Refer to post #27 on page 2 for more information.

Actually it's even more simple than that if you have mages. In our 25m the two mages ( 2 to have one as backup) blink out of the stun and counterspell and the mages can get every interrupt that needs to happen. And if need be one can solo it just fine if you do well and your hit capped.

Ascendant Council Phase 3: When the boss grabs you into his bubble, the healers can let you die. This will proc cauterize, the bubble will end and you can iceblock. Just make sure you dont survive the bubble with low health, as cauterize won't protect you from fall damage.

This no longer works according to the latest round of hotfixes.

I'm a nub posting here, but here are a couple things I've found to be useful:

In general, I play fire kind of like arcane. Burn till I can make use of my evo and mana gem cds, then weave in scorches to make sure I have enough mana to burn after 40% (or timed to be low to evocate again, depending on the fight length).

On maloriak, I found that a well timed combustion basically allows me to solo off all the adds and burst for over 80k dps. Hard cast a pyro when hes about to jump back @ the green phase, load a living bomb, force an impact proc by throwing a blast wave on the whelps, combustion and fireblast maloriak, then flame strike spam, doing another impact dot spread if pyroblast! procs to refresh it. Comes in handy if you get whelps on halfus too.

On valiona and theralion, you keep living bomb on the flying drake for more damage. if you wanna get even fancier, you can keep pyroblast ticking on both as well, tho this will drain your mana faster if you're forced to hard cast pyro frequently to do so on 2 targets.

On omnitron, spell steal arcanitron's buff after he bubbles. Set focus and spell steal tar=focus macros come in handy here.
After their special-bubble-effect expires, I think it's safe to DoT them back up again too (don't quote me on it, gonna check tonight)

Also, on omnitron, try to get a green cloud between you and any oozes that are focusing you in order to benefit from the 50% inc dmg taken debuff.

In throne, a well timed blink can save you from getting shoved off the platform. If you do get knocked off, It will also stop your momentum if you're being thrown in the wrong direction by the winds, resetting it based on your current location and throwing you towards the nearest platform
(this is best used if you get knocked off towards the middle platform al'akir sits upon. If you get lifted up and placed on the middle platform, you will then be thrown out of the zone if you don't blink half way.)

Not so much a tip as a warning but this caught me by surprise: clicking a lightwell interrupts channeled casts. While this seems stupid since you are allowed to click during stuns or normal casts for the time being don't think to yourself 'uh oh, almost dead! Evocate to heal... Oh! a lightwell!'