Haunt and deathfield are pretty much the same thing, if you think of what they do and don't do they both give health back and increase the damage your dots do. When I say castable dot, I only mean in the sense of how haunt was castable and not some aoe I had to drop on the floor. Perhaps I didn't explain myself well there, I was an affliction lock for years so I understand how the mechanic for it works.
It would be lovely if we could place DF where we wanted it be before the CD was over for it,