I have to respectfully disagree with this whole take.
No problem.
First of all, I don't think Buffy/Angel are supposed to mirror or parallel Spike/Dru and neither do I agree that Angel fills the more "traditionally feminine" role by being the "damsel in distress". There is really only one instance in the first half of Season 2 where Angel could be classed as the "the damsel" and that is What's My Line Pt 2. The rest of the time he and Buffy fight as a unit, equals, a partnership. This is the strength of their relationship before Angel turns - they are warriors together and help one another in the fight.
In season 1, 2 and in the beginning of season 3, Buffy has always the main role in their relationship, and she saved him many times (in season 3 when he was feral, she saved him from Faith, Gwendolyn Post, Balthazar etc,), they started to fight as a unit only in the last episodes of season 3 and in the crossovers of ATS season 1.
Also, Angel in seasons 2-3 and Spike in seasons 6-7, during their relationship with Buffy, were shown many times undressed or naked in order to appeal to women and girls' views and represent them as objects of desire and affection as women and girls (undressed and naked) are typically shown in movies, tv shows, and magazine in order to appeal and attract boys and men.
In What's My Line, the comparison of the entire season between Buffy-Angel and Spike-Drusilla, for me, was obvious:
Angel and Drusilla were tied up together and Buffy and Spike fighting defending them, in successive episodes, coincidentally Drusilla regained her strength (Spike got injured), and Angel turned Angelus reversing the roles of their relationships.
When Spike got handicapped, Drusilla regained strength and Angel turned Angelus; the roles reversed:
-Angelus had a "more traditional masculine" role with Drusilla (also the gendered masculine ending -us of the name "Angelus" compared to the name "Angel" that doesn't have a gendered ending, and it can be used for both male and female)
-Spike, instead, in a wheelchair was "in a weak role" like Drusilla was in the beginning (the injured)
The ending fights of season 2 (where Spike allied himself with Buffy):
1) Angelus vs Buffy: The main role
2) Drusilla vs Spike
It is directly linked to physical strength, in Btvs seasons 1-2-3, Angel were depicted a lot weaker (for example, in season 1 he was unable to kill single vampires, he was afraid to help Buffy fighting The Master, he runs away from Spike and his group with Xander in School Hard) etc).
In his show, writers made him stronger in order to reflect the "traditional masculine role of the hero".
Angel started as having difficulties fighting a single vampire (in BTVS season 1-season 2) to being able to kill multiple vampires and demons on his show defending a whole city.
Also, to only focus on this particular time in Darla and Angel's relationship ignores the hundred and fifty years they were together, in which their dynamic was anything but traditional, especially since, as Angelus' sire, Darla was often the leader in their partnership and the matriarch of The Whirlwind.
Yes, since Buffy was a show that tried to give more importance to girls/women, Darla has also the role of the matriarch (like Drusilla sired Spike). However, Angelus and Darla/Angel-Darla followed a more traditional pattern compared to Buffy-Angel.
For example, with The Master:
Darla was the typical subservient "daughter" that was afraid and followed The Master, instead Buffy was the one that killed The Master.
Angelus was the one that defied and mocked The Master, "freeing" her from his authority.
