I posted similar thoughts on another thread, but I'm absolutely gutted by Larian's choice to have Minthara break up with you if you reject Bhaal.
Minthara loves power, but the one price she won't pay for it is her own free will. I'd argue that extends to Durge, her lover, the person who saved her "from [being lost to] madness and blood", the person who rescued her from Moonrise when "I didn't think anyone would come for me".
When Durge inquires whether Minthara empathizes with Ketheric, she says, "It is a sharp mind that empathizes with others, not a soft heart". She and the Narrator outright state that Minthara is fiercely loyal and genuinely loves Durge. She wouldn't want her lover, the person who was there for her when no one else was, literally the only person she trusts now that she's abandoned (and been abandoned!!!) by Lolth and the Absolute, to become the puppet of a chaotic evil murder god.
I can come up with a hundred reasons why, but to name a few:
One: it's risky. Bhaal is very much Chaotic Evil, and although Minthara is undeniably horny for you when she finds out you're a Bhaalspawn (and thus the ultimate predator), she also states that control is paramount. She doesn't commit violence for violence's sake, she does it "to teach [those who have wronged me] not to anger me again". Violence has purpose. Bhaal's violence rarely does.
Two: Dealing with the gods comes with strings attached. She literally saw what being a servant of Myrkul did to Ketheric and views him as a cautionary tale. Sure, Bhaal can provide immense power to his children, but if Durge said, "Hey now, I don't want to be in the position he was in... or the position you were in with the whole Absolute charade, either," I feel like Minthara would take those concerns seriously!
Three: Orin. Sure, she's dead now, and Durge killed her -- but she is associated with Bhaal. Are you telling me that Minthara is going to throw a fit over rejecting Daddy's approval after everything Orin did in his name? After all the trauma Minthara endured at Orin's hands? She's much more logical than emotional, but I can't see her completely ignoring the connection between Orin and Bhaal. That association has to fucking hurt. If I were her, I'd want to wipe my hands of the whole fucking family after how they wronged me, you know? Plus, BHAAL WAS BEHIND THE ABSOLUTE, WHICH MIND CONTROLLED HER. So he isn't just this outside player she can change her mind on and suddenly start admiring.
My comment is getting long, but I'm just so, so hurt by this. This is my favorite game of all time, and my favorite way to play it was just ruined. I don't see why our Durge can't remind Minthara of her own stated principles with a persuasion check, at least? She obviously loves them and is loyal to them by that point in the game. Why wouldn't she even give them a chance to share their thoughts?
Part of the reason it hurts so bad is that Larian did an excellent job of portraying Minthara as a whole person. She's evil, sure, depending on how you define evil. But she's not thoughtlessly evil. Her decisions are all logical and, in her mind, beneficial to her. She is often cruel, but usually to protect herself or to gain some advantage, because she fears being hurt by a world she mistrusts entirely.
Having her just automatically approve of the "evil" choice (accepting Bhaal's gift) simply because it's "evil" and she is "evil" and "evil" characters should approve of "evil" things completely ignores the fullness and richness of her character up to that point.