Been playing frost since BFA, CE raiding and some title m+ seasons, I’ve also been pretty involved in theorycrafting and APL work for it since 2022.
Let me start by saying I like the interesting ideas in the Frost rework, I think theres a lot of things that have changed for frost here that look exciting. Now lets talk problems.
Splinter Resource Generation
Splinters and splinterstorm generating freezing causes a massive influx of freezing around cds, a problem that S1 DF also had which also led to its large amounts of ice lance spam.
Splinter frozen orb cdr is good, but so was a hasted orb. The problem is since spellfrost teachings is flat cdr you double dipped from the haste value. You have the tech to change cdr based on haste, if this was employed on spellfrost teachings, and Orb scaled with haste again that would be great.
Spellslinger already gets pseudo haste scaling from SFT, removing base haste scaling from orb prevents Frostfire from the same opportunity.
Splinter Targeting
Its been 2 major patches since FiredUp did his bug abuse, it would be great if we found a fix that let splinters actually hit your primary target again. Currently they will hit anything you are in combat with, which hurts us quite a bit when splinters can apply freezing, but also like to hit the pylon that is taking 99% reduced damage on Forgeweaver 
.
Force of Will
This talent is a bit awkward, as since you just increased the base Ice Lance shatter to 4, Spellslinger’s Polished Focus makes it 5, and to not lose a splinter youre forced to always take Heart of Ice. Also Comet Storm was increased to 2 freezing consumption, but this node is still specifically Ice Lance?
Ray of Frost
I do think some way to protect this cast would be nice. Personally I think old Ice Floes staying as a choice node with Shimmer wouldve been perfect, especially as fire wants it to protect pyroclasm casts. But we’ve yet to see what the Frost tree iteration is aside from some early datamining.
Frigid Focus vs Splintering Ray
This choice node feels very punishing. We have to destroy any value Ray’s damage has on anything but 6t+, just to get access to AOE freezing application on our main CD. Honestly it feels like they should be merged into 1 point, or frigid focus removed and base ray buffed. I dont think theres a world where the sides of this choice node being overwhelming ST vs basic AOE functionality feels good to choose ever.
AOE
Fingers of Frost
I essentially never get this unless its from Flash Freeze or Glaciate, which is a symptom of the ice lance rotation to be fair. But also, Flash Freeze is currently giving you max FoF stacks per Glacial Spike, which seems unintended. Honestly, I rather like it.
This should cleave to the max targets regardless of freezing stacks. Otherwise youre very punished for spending Fingers of Frost without waiting for your blizzard and orb to RNG give you freezing, or you save your Cone of Frost to ensure your FoF will cleave the max targets. This is a bit unintuitive, and certainly going to cause a major damage and skill difference in frost mages that understand how this works, vs those that dont. Highly recommend it just cleaves to the max targets possible for ice lance.
You removed my Weakauras, add a 3rd Fingers of Frost overlay for its 3rd stack. And add it to the cooldown manager tracked buffs.
Also Improved Clearcasting is 1 point for +2 max stacks, feels like Icy Hands should perhaps be the same.
This needs to function with effects that consume freezing, currently you are unable to proc Hand of Frost while using FoF. And I would be shocked if consuming freezing didnt show up on at least 2 of our tier sets this expansion.
Winter’s Whisper
This is a pivotal AOE point and shouldnt be pushed behind the 2-pointer of Glacial Attunement. Making it or freezing winds a capstone off each other would be a really good thing. If Winter’s Whisper stays locked behind Glacial Attunement it severely limits build variety for M+.
Tab Targeting
Due to ice lance not cleaving unless freezing is on a target, youre often forced to tab target and flurry prior to ice lancing to force additional cleaves onto your 3rd or 4th target. This feels terrible.
I’m testing this while Blizzard isnt working for freezing application, but even with orb out the generation is inconsistent in lower AOE counts.
Frostfire
Comet Storm
This does not feel worthy of a capstone, and its trigger is too infrequent. Also please increase its radius.
The big problem with this aside from it not interacting with Force of Will, or Master Lancer, is its infrequency of use is juxtaposed by Spellslingers frequent use of Orb. This coupled with the fact that FF has to invest the 4 points in the 3rd gate to always take it, really harms Frostfire’s build variety, and it doesnt come close to the power feeling Frostfire had for it in the War Within.
Frostfire currently suffers from a lack of consistent AOE options, and minimal freezing/shatter interaction. Since it has infrequent access to orb, its freezing generation in AOE is poor at best. Which makes it quite hard to get the benefit of all 16 freezing stacks that Comet Storm is capable of shattering.
Frostfire Shatter/Freeze Interaction
I would suggest a shift for Frostfire. Instead of Blizzard, let Comet Storm permanently replace Orb. Have each of its comets guaranteed applied 1 freezing, but Meteor consumes 10. Frostfire then has a bit of a self contained combo, where you Ice Nova → Comet Storm to have a massive burst of damage.
Additionally this would be a theme. Pyroblast and ignite have no purpose atm for Midnight frost. This could be tacked onto them as well, with Pyroblast shattering a stack or two of freezing. Since it hits before Glacial Spike, this would allow Glacial Spike to re-apply the amount it currently does (and you can just flurry prior to casting it to ensure there are freezing stacks for Pyroblast).
Ignite’s place could be as a passive way to reduce Comet Storm’s cd. Similar to Spellfrost teachings.
This could equalize both specs in sustained AOE, while providing them different flavors. Since Orb provides more freezing it should be the more attractive option for Spellslinger, but if spellslinger wants burst it would be able to talent into Comet Storm for burst freezing and damage.
Alternatively to solve Frostfire’s AOE problem you could make Frostfire spells that shatter do a % of that damage in AOE.
Frostfire Empowerment
This feels great, especially when used on Glacial Spike. However, its rare you are able to use it on Glacial Spike outside of right after Ray, because this is only proc’d by Frostfire spells. Given we cast very few of those in AOE, it would be great if this was changed to all spells. FFE has always felt the most awkward when it procs while chain casting frostbolts, and thats the most likely scenario for it to proc in for midnight Frost.
Master Lancer
Doesnt work with any other consumer, this talent needs a rework. Its terribly strong and honestly the backbone of the midnight spec atm driving its complexity.
Deep Shatter
This 2 point node is more egregious than Improved Shatter. Due to how overwhelming Shatter damage is, this will always be taken, and perma locking in 2 points in the 3rd gate is incredibly limiting. As we will certainly be taking other capstones, this can definitely go down to one point. To get it and Heart of Ice → Master Lancer is still more costly in talent points than going from Rimecaster → Flash Freeze → Master Lancer (as an example if you also took Glaciate). So it still adds an additional cost to the middle path.
Freezing
Debuff
For the past several expansions Frost Mages have been using a number of Weakauras with shared functionality called Instant Winters Chill. What this did was on cast of a spell that consumes winters chill, it removed that stack from your UI indication. This was necessary because at high haste or far distance it is incredibly hard to play around a debuff when you have a number of spells in flight.
While the timing of this becomes less important as freezing isnt as restrictive as winters chill, it will still cause reduced player performance and odd behavior on fights like Dimensius and Fractilius, which are quite common in raids these days.
Please implement a maximum travel time for Frost spells, shorter than the current one for Fire spells (this could also be slightly reduced) so that debuff gameplay is not atrocious on a very common raid design, bosses with large hitboxes.
Duration
8s is too short. Festering Wounds had a 30s duration before its removal in midnight. 8s makes target swapping impossible, and that will occur in raids. Since its duration is refreshed when consuming the 8s duration never drives any decision except to really really make you not want to swap targets. Which is generally fine in m+, but will not fly in raid.
Visibility
This is terribly hard to see on nameplates. And yes, debuff on the cd manager will help with this in ST, but not in AOE. If the above duration is increased to 30s it would greatly help if the stack count was the highlighted part of the debuff, not the duration. Given we are trying to shatter a specific number of freezing.
Deaths
Splinters transfer to another target when they die, freezing should do the same. If target swapping is so limited we shouldnt be punished for sticking with our target till they keel over.
Freezing Generation Rate
This is really high during cds, and kind of bad outside of cds. You can not consume all the freezing generated during your cds, and I think this is what drove the increased shatter by ice lance change recently. But that only makes the out of cd rotation feel worse, as you run out of freezing faster. So the delta between the amount of freezing you get during cds and how quickly you are able to use it out of cds needs to be adjusted.
Cone of Frost
Please move this above Freezing Rain. In raid if I want to do cleave I am at the least taking Fractured Frost and likely Splitting Ice already. Cone of Frost is not terribly strong and gating it behind Freezing Rain makes it likely that Blizzard will be cast in ST when talented, and causes me to waste an additional point for something I dont want, sustained AOE.
Empowering Cone of Frost in the Frostfire tree (replacing Dual Casting Adept) could also be a solution to Frostfire’s poor amount of consistent freezing in AOE.
I can see why you may not want to, if it would make us cast CoC/Ice Nova in ST, which would be less than ideal. A similar target cap restriction to Coldest Snap for more ease of access would be great.
CD Imbalance
Current Cone of Cold has a 7s cd with Time Manipulation, and Ice Nova has a 20s cd. These need to be equalized or we will need to be in melee more than we have been in the past. Of the two I’d say making them both 10s cds with Time Manipulation, and having Ice Nova not root with Cone of Frost talented would be great (disruptive to have core abilities root, the root removal from Glacial Spike should be followed).
Piercing Cold
We have no way to increase the crit rate of our base spells anymore, this should be changed. Also Pyroblast should be included in its list of effects. Frostfire’s Glacial Spike is tuned with that as part of its damage in mind, yet it interacts with none of the relevant talents nor benefits from things like using FFE on Glacial Spike.
Glaciate
This talent feels very good. However since it generates 5 icicles and you are only ever at 0 when you just cast Glacial Spike, it does feel a bit bad to always overcap on at least some icicles. Would be nice if icicles could stack a little higher perhaps to account for this overcap.
Can not repost harder. Amazing points that really need to be considered.