what sheakspeare want us to think about iago's character

Wow, this is a loaded question, as Iago is the worst villain in Shakepeare's writing. We're meant to loathe him, be repulsed by him. There are no excuses for his motives or his actions, and our feelings of revulsion are meant to grow with every line he speaks.

Even more, Shakespeare wanted us to fully comprehend Iago's intelligence, and the fact that that same intelligence equipped him with the tools he needed to pull off such a ruse. Everything Iago did was well planned and thought out, he wasn't a jealous lover acting out of emotion, he was an evil being acting with malevolence.