I don't concur, adding Nash means more regular seasons wins, however, come playoff time, he's a defensive sieve and won't be effective once the pace is slowed down and he can't have the in-transition offense in full force.
With Howard, the Lakers simply shift their focus from Kobe ball to the Nash feeding Howard down low type of game. KG is already adept at keeping Howard out of his shooting comfort. Soon, others will learn to do the same in the WC. For Kobe, any offensive which doesn't start with him is anathema. He wants the offensive to continually flow through him, using Nash or Howard, when double teamed.