Just wanted to provide some public feedback about how lame it feels to play Hellcaller and how this impacts build options for both Destro and Aff.
In short, Hellcaller lacks an impactful gameplay loop. Mechanically, the spec’s default DoT is replaced with a MUCH stronger DoT (Wither) and that’s now most of your damage. This new DoT does more damage when you use spenders, which is something you did anyway so you don’t make any decisions differently. Popping Malevolence is something that should always be done on cooldown because of this self-contained design: Wither gets to Wither harder.
If I consider perhaps the best possible scenario for Hellcaller it’s when playing Destro with a Cataclysm → RoF → Malevolence → CDF sequence. But this combo doesn’t feel nearly as good to play as the alternatives. Soul Harvester Aff gets a MASSIVE burst off succulent souls from Soul Rot and the sound effects match the impact. Diabolist Destro can chain tons of RoF casts into any of the summons and enjoy the meaty impact of a Ruination or the Overlord’s slam. By contrast, playing Hellcaller lacks both the UX and player engagement that would make this tree desirable.
Since Hellcaller isn’t particularly fun to play, why would we? It’s usually the weaker choice in terms of raw DPS at time of writing. So Aff is playing Soul Harvester and Destro is playing Diabolist. They’re more fun, more impactful, and do more damage most of the time. The upcoming nerfs to Destro feel worse on account of this discrepancy because we don’t want to retreat to Hellcaller as an alternative hero tree.
With the negative feedback out of the way, here’s a little solutioneering for inspiration. To solve the problem of “Hellcaller doesn’t feel impactful,” we could give the hero talents more power. Seeds of Their Demise could give 2 stacks of Backdraft instead of 4% haste, for example. Or we could add interactions to already powerful warlock spells. An easy solution may be to provide a direct damage or duration amp interactions with CDF and Vile Taint/PS. Finally, we could give better sound and visual design to Blackened Soul to at least give the impression that the player is doing something. Or any combination of the three.
My pie-in-the-sky solution for Destro+Hellcaller is actually an interaction with Internal Combustion. Currently, Chaos Bolt doesn’t appear to consume any of Wither’s duration with Internal Combustion, which seems like a bug. However, if it did consume duration and did more damage based on the stacks it consumed, that would provide a positive interaction with Malevolence! Hellcaller could also passively allow Shadowburn to use Internal Combustion. This would provide players build options that lean into either Shadowburn talents for massive execute damage or into CDF since they now have a way to convert Wither duration into damage via Chaos Bolt. Either of these sounds like a significantly more compelling gameplay loop than what we have in game at time of writing.