Typically, a revenge play in the classic sense of Seneca is a play where a leader, nobleman, or family member is murdered and the play is centered on avenging that death. Classic revenge plays tend to have lots of plotting and scheming and the occasional insane lapse of logic as the characters try to get the murderer. Titus Andronicus and Hamlet are classic revenge plays.
Othello is about revenge: Iago's revenge against both Cassio and Othello. He hates that the "arithmetician" Cassio got promoted over him and that Othello is thought to have "leaped into his seat" (slept with Emilia). But the revenge would not have gone very far without the jealousy—Othello's jealousy of Cassio's better breeding and Iago's jealousy of the other two men.
Of course it's about revenge. The main theme is about jealous mistrust. The relationships of Othello to Iago and Desdemona are paralleled in those between several minor characters in the play. Iago victimizes Roderigo, who wants revenge. Cassio's flip from distrust to trust of the villain echoes throughout the play, and plays on Othello's loss of perception. It seems everyone is out for revenge, but it is more obvious in Iago's villainy and Othello's jealous rage.
I believe Othello is about revenge. More than that, though, I would say it is about jealousy because jealousy is what initiates the desire for revenge. Iago is jealous because someone else is promoted over him. So he plots to get rid of the objects of his jealousy. When one plot fails, he has to get rid of the witnesses. Othello is jealous when Iago convinces him that Desdemona is unfaithful to him, and we know what comes of his jealousy.
Yes, the play is about revenge, but it is revenge born of jealous rage.
Yes, it is a revenge play. The main themes of this player are revenge, jealousy, and mistrust. However, mostly it is a revenge play. Iago is the main villian who wants to take revenge from Othello as well as from Cassio, and he weaves the whole plot. He did so due to revenge. Iago wants to take revenge from Othello as he thought that he slept with his wife but this is not the main reason. The main reason was that othello promoted Cassio instead of him. Iagon thinks that he is suitable for that post due to which he wants to take revenge from Cassio too. But, in all this Iago involves Desdemona too who was innocent:(