Wayne Parr is Mr. Goodlookin', but he's also just an empty suit. To be frank, the guy does nothing at all but, well, look good. Still, somehow, he's "grand marshal of [their] daily parade" (4.6). What Leo means is that, despite the fact that he has nothing to say, people really care about what Wayne does and thinks (not that he's doing much of that). They mimic him because they want to be cool.
But here's the thing: Wayne isn't cool at all. He's completely disconnected, finds no joy in anything, has no opinions, and doesn't excel at anything in particular.
Leo finds the fact that Wayne is so excellent at being both so dull and yet so influential very interesting. Because of this, he thinks he would be a good subject for the "Hot Seat." When he appears on the show, though, Wayne is dull as ever. Kevin asks him who his hero is and Wayne responds that GQ (a men's fashion magazine) is. Someone should really tell this kid that a magazine can't be a hero because, well, it's not a person. We learn just a moment later that Wayne wants to be a fashion model. Surprise, surprise.
For a while, Wayne's path through life changes a bit when his role as "grand marshal of the daily parade" is momentarily taken by Stargirl. She's the total opposite of Wayne: she never wears makeup, is interested in just about everything, and genuinely enjoys chatting it up with others. If ever there were a pair of opposites, it's Wayne and Stargirl.