I agree that there should be a switch of superstars, but some superstars are kind of "made" for their respected brands and shouldn't be moved. One of these people is Chris Jericho. While he was originally drafted a Smackdown superstar (and he is by the way a good fit on both RAW and Smackdown!), you need to remember one slogan: "RAW is Jericho!".
It also kind of the same situation for HBK. I think he's only appeared on Smackdown! once (On the VERY FIRST Smackdown! in 1999, when he refereed the WWE Title match between Triple H and The Rock, and then hit The Rock with Sweet Chin Music). And he's also one of the superstars, that I personally think, put RAW on the map. He was a key member of DX (and the NWO, i guess), and i think RAW would really hurt if they lost him.
But ya I was going through the Smackdown Archives a couple days agos, and i noticed that Cena had a lot of victories, but most of them were against wrestlers like the Bashams and Rene Dupree. So i think he should either start to fight better superstars on Smackdown, or go to RAW, where we know he will fight better opponents (personally I think hes a better fit on Smackdown!). Tajiri and The Hurricane should go to Smackdown, so they can at least compete for the Cruiserweight Title, and RVD should come back to RAW, because he's better known as "Mr. Monday Night" than "Mr Thursday Night".