Success, other than a person's own interpretation, can be measured by assessing the writer's intention because, if the writer achieves what he set out to then, essentially, the play is a success.
Othello ... possesses a power that is perhaps more immediate and strongly felt for operating on the personal, human plane
which immediately connects the audience and allows it to imagine the situation as if it were real and intimate.
The themes are also indicative of Othello's success. When Iago claims, "I am not what I am" (I.i.65) we already begin to see that appearances may be deceiving. Iago will retain his need for revenge throughout and he will "turn her virtue into pitch."
(II.iii.346-355). As the epitome of evil, Iago
is able to twist the distinction between what something is and what it appears to be
and it is this very essence of him that determines the outcome of the play. Even though Othello could, at any point have discounted Iago's claims and, without Iago's input,
fanning the flames of murderous jealousy
Othello's jealousy would not have had such disastrous results.
Shakespeare skillfully reveals how misunderstanding and circumstances can change dramatic events and his use of Iago, the master manipulator, serves this purpose very well.
To enable audiences to draw their own concusions Shakespeare always allows for interpretation. This in itself proves the success of Othello. Was Othello responsible for his own downfall or was it all Iago's fault?