I read this from a warlock on the beta forums:
Bane of Agony has stacks now, and at 10 stacks it does the most damage, so it looks like the idea is to keep it from falling off, so to intentionally clip it.
I think Blizz is getting a little carried away with *cool* ideas and what's practical with Bane of Agony.
Let's keep in mind that Bane of Agony is also limited to 1 target now. This makes warlocks extremely locked into 1 target a time. If an aff lock needs to switch their BoA to a new primary target, this is extremely punishing.
Dots have inherant ramp up, I don't know why the ramp up needs to be this extreme for BOA. How is my theoretical damage I'm balanced around ever supposed to reach that point in pvp when mages, shamans and druids all have dispel curse? Mages even get a glyph that increases their damage by 10% for dispelling it. Let's not forget Iceblock, Clos, pally bubble, etc
If haunt is still in MoP (as I understand a 40% single target damage buff for the warlock that costs a soulshard?), plus affliction warlocks can only channel malefic grasp on 1 target a time, why is Bane of Agony limit 1 target? It's easy to point at affliction's multi target damage and single it out as overpowered, but affliction warlocks have a lot of downsides that the advantage of multi target damage is supposed to be an upside for. This spec has a lot of ramp up, is going to be hell dealing with 8 second cooldown dispels that dispel every debuff on a target and has zero burst. If affliction doesn't have multi target damage, then why should there so be so many downsides?
If anyone's in beta I'd also like to know what happens when you use soulswap on a target with bane of agony. If it just removes bane of agony because it's limit 1 target, then soulswap is pretty useless. I can just manually cast UA+corruption on a new target just as easily.