Maybe it's not the size of Hardy and Jericho; it's that both men are really good as heels. If Chavo were as good as drawing heat as either Hardy or (in his wildest dreams) Jericho then the division would be seen as more of a draw. They need a strong heel champion who can work well with the various cruiser styles in the division. It doesn't really have anything to do with the guy's weight. If that was the case, then you could say someone like Rico or one of the Bashams or GMS would make the idel CW champ right now.
Hell, lets make a call and see what X-Pac is doing.
Being a strong heel champion really has nothing ot do with the worker's size.