Well, idk about much about Soulburn: Haunt since I'm Demo/Destro by I imagine it's irritating to have another soul shard spender to add into the mix.
Demonbolt - cool animation, pretty interesting spell, turns Meta into a cd again, makes Soul Fire almost unusable and causes mana issues because your using Soul Fire outside of Meta. What if Demonbolt restores mana when it's used? For instance you're doing your normal rotation, mc procs, cast Soul Fire until almost oom or full fury then pop meta and Demonbolt to do damage while restoring mana?
Charred Remains - basically switching normal destro play style for Chaos Bolt spam with little dps difference. Either should lower the incinerate/conflagrate to 30% or let Chaos bolt have a chance to be an insta cast proc
Cataclysm - again cool spell and effect but very situtational and hard to pull off well. Should probably be a cd that effects aoe making RoF auto applying immolate, HoG having a larger splash distance and shadowflame dot lasting longer, and Seed of corruption applying corruption.
Demonic Servitude - This one is the most awkward for me because I'm used to getting my embers/fury up, popping ds, then summoning my doom/terroguard and this talent takes that cd away for a pet that does slightly more damage than a regular pet. I think Demonic servitude should be a demo only talent that allows the warlock to summon a second but less powerful demon that just auto attacks and does its special attack. For instance you'd have your Wrathguard with normal abilities along side a felhunter with just auto attack and shadow bite. Or if that is too hard then what about a talent similar to Hunters Stampede?
As for Destro/Affliction specific talents that could replace Demonic Servitude I have two ideas.
For destro: the talent could be that when Chaos Bolt hits a target, Shadowburn has a 20% chance of proccing allowing a single use of it regardless of target health and doesn't consume an ember.
For affliction: the talent could bring back drain soul but instead of a channel spell, it has a chance to auto cast from Unstable Affliction.
I dunno, these might be op dumb ideas but right now locks are pretty awkward. Playable but awkward.