this helps the t12 4pc a bit i guess
few points to bear in mind, assuming it's gonna duplicate then -
haunt 46% (glyphd... duh) inc dot dmg for 12 sec? win
immolate 2x = what will happen to conflg? possibly a win
HoG - if 2x meteor shall fall, perhaps a 20% crit inc to demons will be applied? win
Drainsoul 2x? overkill
demonology 2x hellfire/immolation aura?
onto pvp
seriously the 2x haunt thing should go talented 46% inc dmg *ahhh*
2x soulswaps? this effects pve as well, but no one pointed out soulswap got some minor dmg while applied if it get copied ... tooltip should be funny though, "Copying 3 dots to a target and copying those 3 copied dots from the last target to the same target again".
2x chaosbolt might seem ... fair (the cb should get like 100% dmg inc anyway beside legendry procs to make it viable if you ask me..)
and i guess i could think of some more cool-probobly-not-gonna-happen effects...