Othello - Character of Iago

How does Iago`s goals change during the story? Does Iago’s play evolve during the story?
His goals changes during the play, however his motives are the same. Iago’s play evolves during the story, as he has to improvise because everything does not work out the way he had planned it to do; Cassio does not get killed and Rodrigo gets hurt, therefore Iago has to kill Rodrigo to ensure that Rodrigo can not rattle on him. In addition, his wife (Emilia) rattles on him when she hears the truth about him. Subsequently, he kills Emilia, which was not originally a part of his plan. In addition, Iago’s plan appears to succeed when Othello kills Desdemona, who is innocent of Iago's charges. But shortly afterwards Iago’s treachery is brought to light by Emilia. As a result of this, Iago kills his Emilia, which was not originally a part of his plan. And subsequently, Iago is placed under arrest. He remains famously reticent when he gets pressed for an explanation of his malicious conduct:
“Demand me nothing. What you know, you know.
From this time forth I never will speak word” [Act 5, Scene 2, Line 300-301].

Do Iago succeed in his plan? If he does, in which way does he succeed?
Ultimately, Iago plan apparently does not succeed. On the other hand, I believe that Iago feels disregarded due to the fact that he in spite of being held in high esteem does not get recognition in form of a good position as lieutenant. In consideration of this, Iago succeed in the sense that he manage to get heavily influence; he is no longer overlooked. Hence, it is a victory in itself that he has managed to get that much influence; he that possibly has been disregarded through parts of his lifetime. When taking a closer look at his character, he is disregarded by the senators whom does give a damn about him. And above all, Othello gets the position as a General being black, and besides, he obtains Desdemona as well even though he is much older. So my conclusion is that he in some sense...