Cordelia should have discovered Angel when he returned from Hell in Season 3 instead of Buffy
I was thinking about this the other day.
Imagine Cordelia driving home alone from The Bronze and she almost runs over a newly returned from hell Angel. When she gets out to check if he’s okay, she immediately recognises him.
She takes him to the mansion and chains him up like Buffy did, but she immediately tells Giles the next day in secret. He’s absolutely stunned, but agrees to keep it secret from Buffy and the rest of the Scoobies.
For a while, she looks after him, bringing him fresh blood for him to drink, etc, all without Buffy knowing. Giles struggles with the news of Angel returning, and goes to confront him in the mansion. They have a heart to heart, and once Angel explains how he had no idea that he killed Jenny, Giles forgives him.
However, Xander grows suspicious of Cordelia and begins to worry about her seeing another guy. One night, he follows Cordelia as she’s walking to the mansion. Once she gets there, Xander is flabbergasted, and is irate when he sees her and Angel together.
The next day, a furious Xander confronts Cordelia alone in the Library. As they’re arguing, Giles walks in and stuns Xander by revealing that he knew all along and that he’s forgiven Angel. Unfortunately, Xander takes it very badly and explodes, accusing them both of “pampering a psychopath.”
From there, there are so many options. You can have Giles and Xander fall out completely and the Scoobies not understand why, you could Xander blackmail Cordelia into keeping the secret, you could have Joyce accidentally see Angel as he’s walking down the street, etc.
This was a real missed opportunity to do something totally unique with Angel’s return, but Joss totally dropped the ball.