Well, since Cander was hot and heavy at the time, I think the retribution would have been (or attempted to be anyway) pretty heavy from Xander's end and directed at Buffy's inability to kill Angel. He never specifically blames Buffy but his relationship with her would have changed completely and permanently. And for that matter, so would his relationship with Willow. I would imagine she would attempt to comfort him and a more direct Oz/Willow/Xander triangle could have been berthed. Not to mention Cordelia's humanizing effect on AtS, and the camaraderie they build as a result.
I don't think Buffy herself would have been nearly as driven to kill Angelus as she was after Jenny's death if Cordelia were gone instead. Emotionally speaking the tie wasn't there at that point, not to the extent that it was by even the end of season 2 and beginning of 3. In short, it would have changed a lot, about G/J canon, the Scoobies relationship, and later on, Angel himself.