Doc Ock has it pretty right.
Rami ended each villains career based on what happened in their story arch.
Green Goblin: He dies to pay for the sins he committed in his life, as well as a direct result of his own actions.
Doctor Octopus: He dies to wrap up his story arc and the theme of the film, sacrifice. He sacrificed himself and his machine so that his ideas could live on un tarnished...much like Peter wanted to give up the girl so that he could continue being a hero. It was Doc Ock's passion for his machine and scientific ideas that led to his demise.
New Goblin: He dies to end his arc. He sacrifices his own life to save Peter and symbolizes the theme of forgiveness in movie three.
Sandman: Sandman's arc ends with him going in jail to pay for his crimes. This reflects the theme of accepting responsibility in the film.
Venom: Venom dies and dies in the way he does to show that the symbiot has stripped Eddie Brock to the core. That he was so evil and willing to hate that this hatred went down to his bones. His purpose was to symbolize the overall theme of "great power, great responsibility" that has grown throughout the films. Eddie Brock symbolizes what would happen in a person was given great power without having been raised by a man like Ben Parker with the ideals that he raised Peter with.
Each villains ending served a purpose to his complete story arc. It is tied into the theme of the film they are in and symbolize the characters actions.
Rami's done a good job thus far, no complaints.
-R
t: hahaha **** 
