Any healing class with reliable interrupt should be able to solo it (not easy)
Just equip a PVP trinket, spread the advisors throughout the entrance (first 2 at beginning, caster in al'ars room, and engineer at front of lootreavers room) After that kill weapons (super easy) and loot any legendary that might be helpful (I loot none as a ret paladin)
All Advisors at once: Kill engineeer, by the time he dies, caster will show up (always use trinket to remove her disorient) then kill sanguinar and then thaladred (cause he walks slow)
Once they go down Kael comes running to you, (you should meet close to the entrance that is blocked off) at this point trinket should be up, use trinket to remove the disruption if you can't use the legendary staff and blow all CDs and get him to 50%. Interrupt all fireballs you can and pyroblast (you can eat a few at 85 no problem but be careful) You will have to self heal a lot so be careful on mana as a dps.
Once you get him to 50% it is over, if you die at that point I would laugh. Just burn at a small distance so the orbs dont' touch you, interrupt fireballs and win.
Thinking about youtubing this so people are not so scared to do it. You probably will wipe some to get used to what to do and what CDs to use but overall it becomes easy and oneshottable after you learn what you need to do.