My feedback will mostly center around Destruction, since Demonology has been covered extensively by others and I didn’t play enough Aff on PTR to form an informed opinion. I will speak mostly from the M+ perspective:
Going from 10.1. into 10.2., Destro is one of the specs whose playstyle got significantly worse. This is a result of a) issues within the talent tree and b) the new tier set centered around Dimensional Rift.
Issues with the Destro talent tree are following:
Several choice nodes offer no real choice at all, as one of the options is clearly superior to the other. This is also supported by WCL when inspecting the talent builds of Destro Warlocks in M+ runs. These are following:
a. Reverse entropy/Internal combustion node
Reverse Entropy is so good for how the Destruction spec plays that even when it is slightly behind numerically, it still gets taken over Internal Combustion.
From m+ perspective, this is even more pronounced, as Internal Combustion gives you nothing in AoE, while Reverse Entropy is useful in every situation. Additionally, consuming Immolate has never been an appealing gameplay among the Warlock community (see old Conflagrate) and it is only suffered when the option is significantly better in Single Target.
b. Havoc/Mayhem node
Mayhem is there to provide a passive option to Havoc, which is numerically weaker than Havoc, probably for beginner players. While I understand the intent behind the talent, nobody will reasonably pick it, because even more casual players nowadays pick what is best.
c. Pandemonium/Cry Havoc node
Due to the way Destro plays in any AoE settings, Cry Havoc is completely dead. It doesnt do well in AoE, it doesn’t even do well in cleave/low target count AoE. Destro AoE is completely dominated by Rain of Fire and the idea that someone would cast a Chaos Bolt in AoE because of this talent is preposterous.
d. Inferno/Cataclysm node
Probably the biggest offender. If Warlock wants to do any respectable AoE damage, you just cannot choose anything else but Inferno, making Cataclysm a dead talent. This is doubly aweful, because Cataclysm is a great ability that fills an important hole in the design of the spec - it serves as a burst AoE option and AoE Immolate applicant, both of which Destro is currently sorely missing. It has also a natural synergy with Channel DF, making even that talent better.
In age where other classes need couple of GCDs to do their AoE damage, Destro is there tab targetting Immolates. If the worry is the Immolate spell itself loses purpose, lets compromise and let Cataclysm apply shorter Immolates. You can weave in Immolates refreshes in between RoF casts, the important thing is that you still have the burst and efficient Immolate application even at a price of shorter Immolates.
Solution here is very simple - bake Inferno into RoF baseline and allow us to pick Cataclysm.
e. Roaring Blaze/Improved Conflagrate
This one is about mathematics really - third charge of Conflagrate just doesn’t compare to the power of Roaring Blaze. Solution is to remove Explosive Potential talent which is right next to it and replace it with Improved Conflagrate.
f. Channel Demonfire
I’ve already discussed the solution - making Cataclysm accessible makes this talent much more attractive, even after the loss of current tier set.
g. Soul Fire
This ability has been reworked more times than Shadow Priest and it never really works out. I don’t think what the spec needs, especially after losing Madness and the cast time reduction on Chaos Bolt, is another spell with very long cast time. It might be heresy, because it borrows a bit from a Fire Mage, but listen to me:
Change Decimation from the execute talent and instead make each shard we spend have a chance to give charge of Soul Fire and make it instant. It would give Destro another “high point” in its gameplay, which I think it very much needs.
h. Fire and Brimstone
I had high hopes for this talent being played in Burn to Ashes, however the way things worked out with our build, we never really pick either in AoE.
For me, the dream scenario would be to turn this spell into an active - a damage CD: once pressed, it would make all Incinerates AND Conflagrates cleave all enemies around a target. Give it a 1 min CD and it once again gives Destro some interesting gameplay alternative.
i. Scalding Flames
This talent is not picked due to its position in the tree - while Flash Point opens both Eradication and Ashen Remains, which in turn unlock all three capstone nodes, Scalding Flames only unlock Ashen Remains and Sacrifice, which only unlock two capstones.
I think the fix here is more complex, as this talent is a victim of the most efficient pathing, which is to always go through Ashen Remains and Eradication. Conflagration of Chaos suffers from the same issue.
j. Shadowburn/Conflagration of Chaos
Speaking of Conflagration of Chaos, the talent further suffers from Shadowburn being always the inferior option to Chaos Bolt. Shadowburn just needs buffs.
Problems with a set are as follows:
Unlike the S2 tier set, the current set puts very strong limits on the build flexibility of the Destro spec. While the S2 tier set encouraged us to select a particular talent as well, the position of the talent within the tree still allowed us to make a meaningful choices later, depending on content - we could play Chaos Incarnate/Blasphemy build or choose Grand Warlock Design/Blashemy build for m+. There was also a distinct Single Target build.
Mostly, this is now over, because not only we now cannot use Chaos Incarnate - a major contributor to AoE damage, we also cannot use the Grand Warlock Design node, as we simply need the Blasphemy talent to ensure our consistent damage from pack to pack. And Destro can only ever pick two of the three capstones.
While Chaos Incarnate and Grand Warlock Design weren’t played together, they fulfilled a similar function for Destro - buffing our AoE (and ST) damage considerably - in case of Chaos Incarnate, we just always had the maximum benefit from Mastery for Rain of Fire, while in case of Grand Warlock Design, we got a buff from Crashing Chaos every 1.5 minute (with current version of the talent).
The Rifts will need further significant buffs to compensate for our inability to pick these talents.