Looking at the new Dragonflight talents for locks, I'm overall pretty excited and optimistic.
One aspect that sticks out like a sore thumb is how drain life is being treated as a class ability when it's tuned around affliction multiplying its effect by 750% then using it as an aoe with soul rot. I just don't think it's realistic to balance this for affliction and also make drain life useful to demo/destro at the same time.
There are several class wide talents dedicated to drain life, including one that blocks demonic circle. At this point it seems like it would make more sense to treat drain life as an affliction spell and use the class talents to give a drain effect to spells demo/destro would use.