Smith isn't going to be captain. He's been arrested twice already (IIRC, a DUI for driving a moped drunk and a disorderly for punching a guy at a party). And then, there's the Teletubby carrying his license, claiming to be him. I'm not saying Smith can't mature, but guys like Yzerman, Lidstrom and Zetterberg would never have done things like that. And Smith still looks like he'd be sort of a prick off-the-ice.
On the other hand, I think DeKeyser seems to have the right makeup for possibly being captain one day. Just based on the way he plays the game, and the way he handles himself off-the-ice.
He's not better than Parise. Besides, Parise is much, much better defensively and actually works hard night in, night out. And we'd still have to give up assets to get Stewart. The Blues would probably charge us a higher price anyways.
My last complaint is that I don't get the pun. Maybe if you said Stewart was a dark horse on the trade market?