I've always appreciated Clark Greg as an actor. I first saw him on the West Wing, and his shy nervousness was wonderful. When he appeared in Iron Man, he was a fun little distraction. Throughout the progression of movies, his character gained some volume and depth. He became a person, not just someone to deliver a few gag lines to make the geeks laugh (hey, I enjoy geek in-jokes as much as the next guy).
In The Avengers, we finally started to understand a little bit about the man behind the character. He collects trading cards? He's concerned about "a little boxing around the edges"? That's pure genius from Whedon. It's an instant connection for 90% of the geek fan base.
SHIELD, however, looks like it will take Coulson from a fan favorite to a true hero.
"I've seen giants. The good ones are not heroes because of what they have; it's because of what they do with it."
We've just been given the moral code. This is what drives the most iconic heroes of the past century. The greatest villain is often a twisted mirror of the hero. Their powers are similar and matched. What separates the hero from the villain, is how those powers are used.
That's a great step towards making Coulson a more rounded character.
It was this one line, however, that elevated him to the status of hero:
"Don't ever tell me there's no way!"
There are two kinds of heroes: The gods we aspire to be, and the everyman who rises out of our weaknesses. Coulson is the archetype of every person who has approached the foot of the impossible and refused to slow down.
Cap, Thor, Iron-Man, and the rest are the heroes we want—the heroes we love to see.
Coulson is the hero we need—the hero we can all become. He possesses the greatest power humanity has ever seen: He is a True Believer with a heart of humility.