So who's the main character after all?

  In most of Shakespeare's plays, it's the tragic hero(s) that's given the most amount of lines, soliloquies, and asides throughout the entire play.  In Macbeth it was Macbeth himself (torn between his ambition and haunting guilt), in Romeo and Juliet, it was Romeo and Juliet (constantly expressing their love for each other), and in Hamlet, it was Hamlet of course("to be or not to be!").  So I thought it'd be the same for  Othello right? Meh... okay, so I was wrong. I guess it's partially because all I can remember now from the play is:
"Put money in thy purse!"
"Drown cats and blind puppies!"
"I am not what I am"
"do I ever make my fool my purse"
"I follow him to serve my turn upon him"
"My lord, you know I love you"
"I hate the Moor"
"Honest, my lord!" ....basically all of Iago's rants and conniving plans because, instead of our tragic hero (and supposedly star of the play) Othello, it is he, the villianous Iago, who gets the most soliloquies and asides in this play.  So why does Shakespeare give him the most lines? Probably simply because he lacks what Othello has- honesty.  In fact Othello is probably too honest for his own good because his own honesty caused him to easily trust in others (including, unfortunately, Iago) which allowed him to be manipulated and ultimately led to his downfall. But Iago, because of his mendacious nature (that he tells us himself from the beginning when he says, "I am not what I am" (1.1.65 Othello)), whenever he's talking to others in the play, we never know if he's telling the truth or not (and most of the times he isn't).  Because he's so deceitful when he's with others, we're never able to understand his true inner character and plans until we hear the many soliloquies and asides Shakespeare gives him to allow us readers to better understand his underlying evil intentions.  Otherwise we'd be in a similar situation as Othello, Desdemona, Cassio, Emilia, and all the other unsuspecting characters are in: still singing praises and thanks to "Honest, loyal Iago"!  By allowing the audience to hear Iago's many soliloquies and asides that expose his true nature, Shakespeare is also able to use dramatic irony, perhaps to ensure that audience continues to sympathize with Othello even when he turns on innocent Desdemona because we know that he is driven to that jealous mindset by Iago's manipulative scheming.

  Also, in contrast to his multitude of lines while in the midst of his scheming, by the end Iago cannot defend himself when the rest find out the truth and he only says "Demand me nothing. What you know, you know. From this time forth I never will speak word." (5.2.302 Othello).  I think the contrast between the extensive amount of lines Iago has for most of the play and this last line he has at the end, a refusal to speak when the others finally uncover his lies, is interesting and perhaps symbolic of a change in the tone of the play? Perhaps Shakespeare is hinting to the slightly more hopeful change in the tone of the play, that the truth will prevail in the end? or is it simply because Iago thinks it's futile to say anymore because he thinks they probably won't believe him now that they've discovered he's lied to them all?