Jesse should’ve haunted the narrative much more than he did. He was a childhood friend to Xander, just like Willow. He was the guy Xander was willing to risk his life for in the second episode. He was the guy Xander was told was no longer his friend, just a monster wearing his face. He was the guy Xander saw explode into dust on the point of his stake.
How about instead of making Xander’s hate of Angel about romantic jealousy, make it about Jesse. How come you told me to kill my best friend but you keep Angel around, despite barely knowing him, because you think he’s cute? How come you told me to kill my best friend but you, slayer of vampires, can fall in love with one? How come you told me to kill my best friend but you hesitate to kill Angel who has murdered hundreds, not to mention people we care about? How come you told me to kill my best friend but allowed Angel to feed on you, thus putting your own life at risk for the sake of a monster? How come you told me to kill my best friend, but were willing to chain up Angel and work to rehabilitate him?
Like Xander as a character could keep bad humor as his coping mechanism and still be an idiot about girls, but make him remember Jesse. Make him want to kill vampires more than any other monster because his death had to have been for a reason. Make his hatred of Spike because a self-professed “Big Bad” got more of a chance than his best friend. Make his attraction to monsters because he’s always looking to see if any of them have any humanity. Make him remember Jesse, his best friend.
