Thats completely idiotic.
Bhaal is just one of many deities in the setting and many are evil and equally or more powerful then Bhaal, especially now.
The story of bhaalspawn is OVER.
We do not need a fight with a deity to close his whole story. There is no "final showdown" and you cant really kill a god by any conventional means. Gods are not meant to be enemies with + whatever.
You are only talking about some inane imagined expansion for the first two games. Which isnt connected to this story at all - because we are not playing bhaalspawn - again. So there is nothing our characters experience that would make them want to have any kind of fing "final showdown" with Bhaal.
There is no reason to think the Bhaalspawn plot is quintessential and mandatory for all BG games. It was the plot hook for the first two games - thats it.
The real defining element is "a plot by an evil god or gods giving the player some special powers but at a terrific cost". Any God can serve in theory.
It seems all of the dead three are involved in this plot in some way - and thats a link to the previous games. But it doesnt need to be a defining one. Just like the city of Baldurs Gate is not definitive in any way in originals or now.
You may as well remove Darth Vader from Star Wars. Technically Bhaal is more like Palpatine.
Not really surprising this incoherent mutually exclusive nonsense comes from somebody still stuck on the fing bhaalspawn plot.
Which one is it? How the f can you make these two sentences and not notice one cannot follow the other?
Its not "technically" more like Palpatine - it is like Palpatine, a figure influencing events from the background, with a huge difference this is a God.
Sarevok was actually like Darth Vader, if we really have to reduce everything into dumb SW characters - a dark knight going around wrecking stuff you can actually fight.
Funnily enough, or disgustingly enough, reintroducing Bhaal yet again as the main villain-force would work as well as reintroducing Palpatine in the last SW movie worked.
