For what it's worth (not bragging, just stating), I've killed Kael at 90 without picking up *any* weapons, just burning, self healing, etc. Picking pretty much any usable weapon should make it a lot easier.
I solo him once a week as shadow. I use the staff and cast the buff on myself.
I'm still able to use my shadowfiend without getting mc'ed.
It was easy at 85, now it is a joke. Few tips:
Wait until there are only 15 seconds on Remote Toy before finishing off Telonicus to avoid getting stunned while dealing with the weapons.
Kill the Shield ASAP in the weapon pack as it will interrupt you; AoE the rest.
Equip and Use the Staff to not get stunned by Remote Toy/Conflagration in phase 3 or Arcane Disruption vs Kael.
Equip the Mace and cast Renew/PW:S and you get a 50% fire damage reduction buff for 30 seconds.
Stay out of melee range during Gravity Laps or you get a stacking 10% HP/Damage reduction.
As for soloing Alys. You could do it at 85 once you were about ilvl 390 or so.
Get all the rings to maximize damage. I use FDCL/Divine Bulwark/ToF for talents.
When she flys across the middle the first time use shadowfiend or she might despawn if you get too far away.
When she goes into Firestorm land just outside the Fire Wall and keep Renew/PW:S up. Try keep DoTs up, or at least refresh them before she cashes.
When she gets up use VE and just her wail on you, or Fade and let Shadowfiend tank her.
Repeat until dead, but he should be before the second Firestorm.
100% soloable as shadow. Use the Staff to keep phase 3 from becoming an utter nightmare.
Trust me on this. I got my Ashes doing the fight solo at 90 as shadow. It works.
Bacon is the thing pigs give you when you're good.
To sum up:
Do not use Shadowfiend.
Do not use Mindbender.
Do not use any kind of pet whatsoever.
I just tried it for the first time last night. I sort of had a trial and error session. Clearing (most) trash and A'lar first. I forgot to clear trash on the other side of his room and that's where I died the first time. Second time I died to his Pyroblast once I got him past 50%
Hoping to down him tonight
The issue with pets lies in you being disoriented and Kael changing who his target is. He won't MC his main-target, and he can only MC Humanoids. Pets are okay IF you do not get disoriented. That is how it works.
Ghost Iron Dragonling does count, since it is targetable, so if you wanna be careful, don't bring it.
I mainly play as a Ret Pally, so can't speak to Priest-specific tactics, but I know I've never been MC'd when I used Guardian of Ancient Kings (Ret's Guardian IS targetable and killable). But equally, never been disoriented while it's up (I use it on P3 and if up again, P5, but lately it doesn't take me 5min to do P5).
As to clearing the raid: No bosses have to die, just depends how much room you want. I used to clear out Al'ar, and then one of the side bosses (I did Void Reaver, but that is a caster's nightmare if you cannot cast while moving). Now, I don't bother with any. I just use the hallway between Al'ar, Void Reaver, and Kael, for the whole encounter. But this comes down to burst damage mostly, is why. After you do it a few times, you will find what works for you, to cut down on encounter time.
Games are not necessarily "easier" today. You are just a better player.
It takes more now to impress many gamers than it did 2-5 years ago, because so much has already been seen and done.
Many players expect to be wow'd with every release of a beloved franchise.
These are generally NOT the fault of the developers, but the fault of many players over-hyping and/or setting expectations too high.
You can also start by killing the phoenix boss, then go and start the fight, and run out asap of his room. wait until the first advisor is active, kite him to the phoenix boss room, kill him in the opposite side, wait until the 2nd advisor comes, kill him a bit closer to kaelthas room, do the same with the 2 other advisors. run to kaelthas room, wait at the door for the weapons, aoe them down. and now kill the advisors 1 by 1 as they approach you. wait for kaelthas at the door, nuke him. wait for the last phase and it's a kill.
At least I do that like that. I know that's a hassle, but I like to be safe and not to get cc'd and killed (never liked the weapon usage)
was easy at 85, must be easier at 90
I solo KT every week as Shadow. I do use the staff though just to be safe, but it does gimp your damage. Using my Shadow Fiend has never caused me to be MC'ed or him to reset. If you don't use the staff then make sure to use fear ward, and wait until about 10 seconds are left on remote toy. It's pretty simple besides that.
I solo Kael weekly on my Boomy using the method where you run out of the room before it gets locked off then killing the 4 advisors throughout the instance so that I can rekill them individually. Its certainly not the quickest way but probably the safest and easiest imo. Also as far as Alysrazor goes she is a pretty easy/fun solo. Check some videos on soloing her so you know where to land during her tornado phase and make sure to stay on her ass so she doesn't despawn. Good luck on your mount runs!