I was able to solo this earlier on live as a blood DK.
http://i.imgur.com/g8Zfx.jpg
What you need:
Bare minimum ilevel 359, all DPS gear. Stat priority Strength > Hit to spell cap > Expertise to softcap > Crit. Tank gear will make phases 2 and 3 extremely difficult because they will take too long.
PVP trinket ilevel 352+ (preferrably the crit one)
Standard blood tank spec centered around threat, 35/0/6, taking everything in blood except Hand of Doom, Butchery and Crimson Scourge. I went 2/3 Will of the Necropolis and 2/3 Scent of Blood.
Prime glyphs: Death Strike, Death and Decay, Heart Strike. Majors: AMS, Bone Shield, third doesn't matter. Minors: Blood Tap, HoW, Path of Frost
Prismatic Elixir
Elixir of Impossible Accuracy / enough hit from gear to be spell hitcapped
Runescroll of Fortitude, kings drums, strength food
I reforged into crit heavily as mastery is nearly worthless on this fight and diseases don't scale with haste
A'lar and Void Reaver should be dead, as well as all trash in the instance except for that in Solarian's room and the hallway on that side if you didn't bother killing her.
Engineering saves you some damage and gives you some damage boost, I recommend it. Parachute cloak, Synapse Springs and Nitro Boosts enchants
Strat is basically the same as Raegwyn's video from beta.
Phase 1: Engage KT. Run out of the room and all the way to the beginning of the instance. The doors to KT's room don't close until the first Advisor activates. Thaladred is first. Tank him right by the raid entrance door with your back to the wall so you don't get knocked back out of the instance. Burn him down. Wait for Sanguinar, engage him about 30y inside from the raid door so you don't get feared out. Note the fear can be LOSed. Tank him where you killed Thaladred. Once he dies run back the way you came. Capernian will meet you just outside the doorway leading out of A'lar's room towards KT's room. AMS once you're within 30y of her and run past her, then run all the way back to the now-closed door leading into KT's room. With your back to this door, she -should- run into the previous doorway. Try and get her positioned so that you can stand between her and a wall and not be knocked back out of melee range. PVP trinket a conflagrate if necessary to do this. Burn her down. Telonicus is last, I took him just inside Void Reaver's room (which was empty since I'd killed him already) and killed him there. The first cast of Remote Toy -can- be LOSed here if you're lucky, so burn him quickly. Otherwise if you get the debuff, don't kill him until it has about 10 seconds left on it so that you're not being chain stunned at the start of...
Phase 2: Run back to where you killed Capernian. You'll meet the weapons halfway. Target and kill the Cosmic Infuser first. Interrupt its "heal" cast and drag it and the melee weapons on top of the bow/staff of Disintegration so you can AOE them down with D&D / pestilenced diseases / heart strike cleave. Once the Cosmic Infuser is dead, target the Phaseshift Bulwark and just heart strike cleave off of it until it's dead. Kill the rest. You should probably have 5-10 seconds left before...
Phase 3: The advisors resurrect. Stand between Capernian and the wall. I cast Army/Risen Ghoul at this point, AMSed just before she became targetable, blew cooldowns; Blood Fury, DRW etc. You must kill Capernian as quickly as possible, preferrably before you get conflagged. If you do, PVP trinket. Telonicus will arrive when Capernian is at about 20-30%. Finish her off, then burn him. Don't IBF if you get Remote Toy, you can outheal the bomb damage, just run back and forth through him and most of his casts will miss. He should die just as Sanguinar arrives. Start burning Sanguinar and moving yourself slowly back towards the hallway connecting A'lar's room with Void Reaver's. Tank him with your back facing a wall. He should die just as Thaladred arrives, you will be knocked back the moment Thaladred gets within 20y of you and if you had your back to a wall this shouldn't be a problem. He should die with 10-15 seconds left before...
Phase 4: The moment Thaladred dies, run towards A'lar's room and be about 40-50y from the bottom of the ramp, between it and the doorway leading out of the instance. You may be able to bandage here. KT will cast his first Shock Barrier / Pyroblast somewhere on the ramp. AMS and run to him. AMS will absorb the first 1 1/2 Pyroblasts, mind freeze the last one. Get diseases / D&D up, you will be disoriented at this point. The phoenix adds will kill themselves, so just cleave off of KT with heart strike. Try to avoid standing in the flamestrike AOE under where a phoenix spawns - this will miss most of the time due to level difference but if it does hit you, it hits for about 80K. Save PVP trinket for if your health gets low and you get disoriented. When the phoenix adds die and an egg spawns, switch to it and burn it as quickly as possible to avoid it rebirthing and knocking you back 40 yards. When KT is about to cast Shock Barrier again, AMS with a second or so to go, this will absorb the first Pyroblast and you should be able to burn through the shield to interrupt the next. Repeat until KT reaches 50% and transitions to phase 5.
Note that KT does a mind control in Phase 4. KT -can- MC you, but only during the disorient and only if bloodworms or a ghoul are out during that time. I haven't been MCed yet over 3 solo kills and the ~20ish attempts I put in at first but you can simply spec out of worms if the risk bothers you.
Phase 5: KT will run all the way from where you are back to his room to do the RP / graphics that he does between these two phases. Note that he is still attackable during this time while he is running. He runs a lot faster than you, so get diseases up and use Nitro Boosts to catch up to him to get more damage in if you can. If they fail no loss. You can get him down to 40% this way.
KT will go through the RP. When he casts his first Gravity Lapse of the phase, he will teleport you to him (he will be just outside the door leading into his room) from wherever you are in the instance, and you'll have the flight buff. Refresh diseases, drop a D&D under him and start flying back to A'lar's room, don't bother AMSing or worrying about the damage he does midair. Try not to land before the debuff falls off. If the debuff falls off while you're at a great height, parachute cloak or Path of Frost to negate fall damage. Get back down the ramp to where you started Phase 4, you can bandage here. Strangulate the first fireball cast, AMS and tank him at the bottom of the ramp, burn him as much as possible before the next Gravity Lapse. When he does Gravity Lapse fly away from him, drop a D&D under him and any adds and refresh diseases on him. Wait for Gravity Lapse to end before reengaging in melee. PVP trinket the first disorient if there's more than 10 seconds left before the next Gravity Lapse or your HP is below 50%. You can Army again if you like, but this phase is trivial and he should die pretty quickly.
Collect your free gold, loot and hopefully phoenix mount.
I found the sound tends to bug out during the phase 4-5 transition, toggling sound from "hardware" to "software" and back fixes it.