I would genuinely love it and find it very thematically appropriate if the Dark Bargainer Iconic had access to some kind of a negative strip, this feels like it would fit with Abyss pact so well and that has always been a gimped pact due to how many things are not affected by negative and the major forms not allowing overlap - especially as something that looks like it really wants to stay single-classed like this.
I think this (and some scythe options for quarterstaves, barring a whole new weapon type

) would breathe life into my abyss melee warlock, and aside from a warlock-adjacent epic destiny, I'm not sure if there is currently a better place to insert that option into the class aside from giving love to the Abyss pact itself.
That said, I do really like The Dark Powers as a pact as well and there is a lot of flavor in the Dark Gifts but I also think Abyss could use that little extra bit of love. Not to mention it seems like we're likely going to have a whole bunch of undead to deal with in the near future with the return to Ravenloft.
I really like what I'm seeing and the improvements after the feedback are very appreciated. Looking forward to more iterations!