Isabella threatened Hawke when he got together with Merril and I never started a thread about how pissed I was. Because I knew Bianca and Isabella meant well. OP prolly doesn't understand context.
Know what difference is with Isa and Bianca? Isa is your crew,she is your party,works with you and is your friend who made this "joke".
Bianca you meet only once,she uses you to fix her mess,later tells you truth she is reason how Cory got red lyrium,she doesn't feel sorry one bit and goes with card "Well it's fixed now so what" like her mess never did any harm or is still doing harm and then a person you wish to "punch" in their face makes this "joke".
Now that is main difference! Because Isabela never made such joke after she betrayed you,hell she even stayed out of Hawke's sight for 3 years drinking alone for what she is done,she had enough face to not show up infront of Hawke after what she is done while Bianca has enough face to even ask "so what" after your discover her mess.So now compare two and two and see that beside "selfish" part they have nothing in common.
If I had to compare Bianca with someone I would compare her to both Anders who is most like her and Talis as well.