As I remember W&H doesn't was Angelus, they want Angel to be working for them, because of prophecies and such. Apprently Angel will be a major player in their apocalypse , and they want him working for him, not turned (Angelus is too unpredictable, and a bit of a coward actually) but dark.
We don't know if their end-of-the-world thing has actually happened yet- S5 maybe?- But I always imagined that W&H's it would be THE last big battle that Buffy and Angel would ever fight.
I'm still waiting for W&H to reappear in A&F now that magic is back. They've got tons of new material to torture him with. 😀