Before the introduction of the latest weapons in the latest patch, the hakkon would have been bis hands down. Now, it's debatable. The 50% attack speed on bloody bargain makes it superior to the hakkon for me for Izzy and Pala. Arguably it's also best for Luka, more mine spam during flask, as the animations are sped up, allowing you to drop more mines.
Pala could also use the savage thorn in offhand,
You wouldn't be killing stuff with bargain + duelist outside of perilous, where it wouldn't matter. Or at the very least, your overall killing speed would be far less than with nameless, which has an upfront and immediate damage buff that scales with the number of enemies near you. The same goes for audacity when you kill things nearby, especially against those with low hp (perilous and below). Isolated targets are what bargain is best at when playing Izzy, but those don't need buffs to kill.
I have a friend that swears by bargain. I outkill and outscore him every time when we both play izzy and I use nameless instead. You do move and attack faster as izzy, but that doesn't matter since her best abilities let her dash across the map or kill at range regardless, and benefit more from upfront damage actually getting the kill. i.e. you won't get the kill unless you're playing around scrubs and vastly OP for the situation.
The napkin math does demonstrate the relative damage increase being less, especially against multipliers like nameless blade. Still awesome to have though.
You'd get scenting blood a lot of the time with Pala, which reduces the point of Bargain. Izzy with bargain is pretty terrible since her attacks are all burst, which lends itself to nameless blade upfront damage bonus.
Granted, we're talking about end-game weapons and for most people its less of what we want and rather RNG actually lets us have, so this discussion is moot for a lot of folks.
For example, If I had bosun's I'd try FA with it. I don't, so I can't recommend FA because I haven't used it. As an assassin, you need to kill enemies before they can counterattack, so I can't recommend anything that doesn't allow for that.
I'd actually want to know how bosun interacts with ele mines too. Would there be added damage based upon the position of the player? What about toxic cloud? Evade? I don't have that toy, so I don't know.
Oh you have nothing against Rock?
Rofl, It doesn't seem to get his goat, but definitely gets yours launched. The best part is he's a better player than you hands-down, and still got sloppy on stream, and your group of promo's are terribly great about encouraging sloppy play with each other.
The fact remains you're the one most upset by this.