You guys know me. I love to make up spells and talents. Here's the latest round of changes I'd implement for Cataclysm. All of these given to Warlocks together would probably be OP, but 1-2 of them would be very fun and appropriate.
Instant cast. 3 minute cooldown. Affliction tree/Shadow spell school. Learned @ level 82.
Transfers all negative status effects with their remaining durations from you to your target.
Warlocks are pretty heavily based around debuffs. What better than being able to clear debuffs off yourself and throw them back at your target? In a way it's like a reverse Spell Steal. Mages take buffs from their enemies and put it on themselves, Warlocks send debuffs from themselves and put them on their enemies. This one could be a lot of fun and add a new dynamic to Warlock PvP. 3 minutes might be too short of a cooldown. Or "all debuffs" might be too strong. It could work with a much shorter cooldown but with only 1 random debuff. 45s cooldown to x-fer 1 debuff could work as well.
This ability opens up all types of uses. Getting pounded on by a Warrior? Got Rend, Deep Wounds, Hamstring and MS on ya? Wait until right after the Warrior recasts MS then use transference. You can now be healed up without MS on you and the Warrior is covered in his own debuffs as a nice bonus. Or you're fighting another Affliction Lock. Imagine the metagame around this ability. Whoever uses Transference first actually loses out. You both have UA/CoA/Corruption on each other. You use Transference and the other Warlock recasts his DoTs on you and then uses his. You now have 3 sets of Warlock DoTs on you. Nasty!
Curse Mastery (Master Demonologist of the Affliction tree)
5-points talent in Shadow Mastery's current location since we know SM is a goner.
Through study of the dark arts you have enhanced your curses. Empowers your curses with the following effects:
Curse of Agony: Gives your Curse of Agony a 20/40/60/80/100% chance to apply Curse of Elements to your target as well.
Curse of Doom: Reduces the duration and cooldown of your curse of Doom by 4/8/12/16/20 seconds.
Curse of Elements: Additionally increases the amount of health you steal from the target by 3/6/9/12/15%
Curse of Exhaustion: Increases the slowing effect of your Curse of Exhaustion by an additional 2/4/6/8/10%.
Curse of Tongues: Increases the mana cost of spells by 3/6/9/12/15%.
Curse of Weakness: Increases the energy, focus, rage, and runic power cost of abilities by 3/6/9/12/15%.
Posted an idea similar to this before. I still like it so I tweaked it a bit and reposted.
5 minute cooldown. Is now a buff, no longer channeled.
Surrounds the caster with Hellfire for 8 seconds. While Hellfire is active 50% of the damage that would be dealt to you by sources within 10 yards is instead dealt back to them.
Simple concept here, really. Makes Hellfire not suck. Anti-melee defensive cooldown. Two birds, one stone.