Eh, even then, I don't really think it works. Cordelia just appearing at the end? From seemingly nowhere? That just takes away the poignancy of Angel, Spike, Gunn and Illyria staring death in the face in that rainy ally.
Appearing out of nowhere is just strange, but I have no issues with Cordy staying in season 5. Say SMG did appear in the 100th, I reckon Cordy would of awaken from her coma in Power Play.