It does.
The desync cheese eliminates the buff she gets. When she’s on each side, they channel a laser. Every 4s that she’s in that laser, they power up the abilities used on that side specifically by 10% (and it fades over time). Normally the storm starts at 1 buff (so 10%) and goes up to 40% for the last tick. If you desync the lasers, she never gets a chance to get empowered for the storms. It’s basically a 25%-30% total damage reduction to do it.
You’re going to struggle fitting that many abilities into a 9s storm, especially the second PW:R. Mind Games is also strictly worse than Mind Blast during Bender because it doesn’t proc Inescapable Torment or Expiation.
The issue is that in a 21 Tyran Hyrja this week the storm is ticking for 100k through barrier, 130k without. Standing around for 2s casting a PW:R during the channel is the easiest way to brick the key because in that PW:R cast your team is taking almost 200k damage each and the tick after PW:R is going to kill whoever didn’t get crit.
It could be better with more haste though. My scuffed gear is only at 16% when I’d ideally have ~30%.
My experience with Pally has been similar to yours this week. Went from 350 > 380 ilvl healing 12-14’s and didn’t have a problem with anything. Having Virtue up for every instance of groupwide damage feels like cheating it’s so good. 50% of the time Hpals basically have the ability to constantly top their team while moving ontop of their regular toolkit; it’s nuts.
Which is why you mind blast twice first 
I only mindgames after the first 2 charges are out. You Blast → HD penance to give yourself a bit of MB cooldown, then blast again then midgames.
From what I have done, I’ve definitely had time to cast PW:R, and its one of our strongest heals still. I HAVE gotten through Hyrja on a 20. The group failed after that though. And I’m running 24% haste. Honestly I accidentally ended up in a 17 AV with my 15% haste gear and it was a nightmare. Things I could normally do fine were way harder.
Funny enough somebody said this to me “you must be the last holy priest because everyone’s switching to Disc.”
Holy is just so trash in 5-man dungeon right now there is no reason to not change to disc unless you just love playing holy. Holy is great in raid tho. I am playing holy in raid and disc in M+.
It’s not THAT trash.
I play both holy and disc in dungeon for fun, and nothing is so wrong with holy that it’s unplayable or something. Disc just got a lot of AoE healing and double pain supp is great. That pushed it up, but Holy’s still capable of 23/24 keys. And 23/24 is at the point that you wouldn’t even be pugging anymore anyway - so it’s nowhere near bad enough that everyone should migrate immediately. Especially considering Disc is a much tougher spec to play mechanically, so most players are just going to do worse with it.
At worst it’s like 1 key level behind disc at the very top end. That’s barely worth mentioning for most players, lol.
It’s also impression, by statistic, holy is second worst spec in M+ now (MW monk being worst). As holy, you will be declined to most keys, unless you already overgeared + overIOed.
Holy is having a whiplash effect right now. Before the expansion launched Holy received a -10% hps nerf and now that nerf has been basically reverted with the 6% hps buff + 5% leech.
Holy feels fun in raid, but its unrewarding. I can slam out 3 salvs/hymns/etc. and still be 20-30k hps behind the Resto Druid. A -3% nerf to Resto Druids is incredibly tiny and should have been 10% or more.
Oh man, don’t say holy is trash!
I am trying to not switch back to disc as my brain might explode lol. I kind of feel like I am sort of getting a groove in holy now, though I am not amazing yet like some of you. I have only ran 2 20s for completion and timed only one 19 shadowmoon.
It is super tempting to switch back to disc for some keys, if for no other reason to learn the rotation for some of the harder aoe phases in higher keys where it matters more which buttons you push.
The reality is that Disc is slightly better now. It got a ton of AoE burst healing that can be used frequently - which was its biggest weakness before - it had good burst but once the burst was over it was “off” for a good minute. Disc also got damage on top of it, as well as a talent giving them 2 charges of pain supp which is extremely good for them because you no longer have to worry about letting go of pain supp to cover some of the crazy ST things that can happen in these dungeons.
But Holy isn’t bad at all. It really depends on your goals. If you just wanna get your 20/21s done then it won’t matter what you play. Holy is not bad enough that it’s going to drop you like 2 whole key levels just by playing it or something. In fact, it’s an easier spec so a lot of people will probably do better on it than disc. If you wanna push as high as possible and try and hang with the absolute best of the best with your own premade and do 25-27 keys, then you should probably be playing Paladin, Evoker or Druid. If you want to play priest but also push as high as possible for the class in a premade, then Disc is what you’ll probably want to play.
I just want to be the best priest I can be I guess. Not switching mains. 
I usually play with guildies and right now my goal is just to keep getting better so we can farm 20s for vault. Anything past that right now just seems like a headache.
Valor being uncapped next week will help for sure 
And echo spamming is much better? It’s literally the same.
Echo isn’t spammable 
Getting as much echo out on the group as possible to VE into a cooldown is quite literally how evoker plays at high level. You have tons of ways to generate essence and you plan around that. If anything echo is more clunky because it isn’t consistent.
Granted at a low levels you just hit dream breath and laugh because the button is horribly overtuned.
Excuse me, but what is the cost of Echo?
2 essence.
What is essence burst?
What is spark of insight?
What is Resonating Sphere?
If you don’t think these all come into play with evoker, and blanketing for emerald communion doesn’t happen in both raid and M+, you aren’t playing the class well.
In context capslock - Echo is 2 Essense …a limited resource
If the gameplay is to Flame breath R5 to get leaping flames so you get an immediate 2x essence burst, then you use echo 4x to blanket - it’s the same thing as putting atonement on 4 people, but with an extra setup step.
If the gameplay is to throw out resonating sphere through the group to get echo on them so you can lifebind heal or make your dream breath 30% stronger, it’s again, the same gameplay as applying atonement thru radiance.
That is what the person you were responding to is referencing.
Its literally not the same gameplay as wasting 5 GCDs (when PWR is on CD) to unlock ACTUAL healing but who am I kidding…why would you know
So far this xpac I’ve played evoker, priest and pally a decent chunk.
Evoker is by far my least liked healer of the three the higher in keys I got because Echo feels like a more clunky and less fun version of Atonement that is currently tuned to an insane level because of lifebind and dream breath’s potency.
Your idea of how to play Disc priest is just completely wrong, and you either:
It’s so ‘anemic’!!”) to make your points.This is why so many people have called you out for #3 recently.
Disc priest isn’t ever using 5 GCDs to unlock healing in M+. The max they ever have to do this is 4 and the only time THAT happens is if the priest themselves messed up. Evoker also sometimes stacks essence burst to put out 4 echos. The gameplay is similar. You may not have climbed high enough to know because you can just hit stasis, dream breath, spiritbloom and rewind in some order and push through a bunch of mechanics that way in low to mid level keys. But if that’s where you’re happy, then go play that.