Composer Aaron Copeland had a technique of 'sneaking up' on a motif, revealing it bit by bit before stating it outright. I feel one should do something of the same sort when it comes to the exposition of characters in a work of fiction.
Yes, we want fully realized characters and the author should have a pretty clear idea of who they are (though they will inevitably 'develop' in the course of writing). It's no good to just state outright who they are and give their back-story yet I have seen exactly that sort of advice.
Let that character be revealed bit by bit -- his back-story, his motivations, even his appearance perhaps. Let there be some mystery. Isn't that how we come to know people in real life?
Don't tell us the character is short. Reveal it through his actions or those around him. Don't tell us he was abused as a child. Let him have scars he has kept hidden. But, of course, reveal them eventually.
Any reasonably decent television drama knows to do this (well, not with appearance). Maybe all you authors should put down the novels and watch some TV! :)
At the same time, don't let exposition turn into deus ex machina -- don't spring something on us completely out of the blue just to move the story along or, worse, tie up some sort of conflict. Mystery writers learn this. There have to be clues.
Or, to return to my original example, give us hints before launching into your full theme. Let your audience discover these things. Let them come to know your characters the way they would real people.