The only thing I think you could possibly argue that Blake does better than Nash is defense. In losing Kobe, the biggest thing we lost was someone who can create their own shot. Nash can do that. Blake cannot. And while Blake has been hot, Nash is clearly a better spot up shooter than Blake. And let's not get carried away and act like Blake is MWP on D all the sudden - he's solid on the ball in spurts but also terrible off the ball, leaving his man wide open all the time (lest we forget how Dame Lillard completely torched him). What little we gain in D from Blake nowhere near outweighs the offense, passing and veteran presence from the former 2x MVP and 8x All Star. Come on.
It's no argument that Blake is a better defender, and he doesn't have to be Artest to be that much better (even though Artest's defense has dropped off quite a bit).
Never said Blake did anything else better than Nash...except for fill his role correctly, in this particular offense, on this particular roster...and that's what we need.
Sure, Nash is a better shooter...a 50/40/90 guy. Doesn't help us, though, if he refuses to play off the ball as much as Blake does.
Nash does create his own shot...but when we put the ball in his hands often, we tend to NOT get the ball to Dwight, who is the superstar of this team. Instead, we jack threes off of Nash's facilitating, and we need to stop launching them off of Nash because, quite frankly, he doesn't draw enough defensive attention anymore, and those threes are contested.
What Nash brings on the offensive end, today, is not enough to make up for the defensive issues he drags in with him AND the role he has trouble filling on this team. If our lineup was...
C - Kevin Love
PF - Chris Bosh
SF - Kyle Korver
SG - James Harden
PG - Steve Nash
Then you pretty much don't care about the defensive end, and you know you're going to rack up 100+ PPG and still be able to use Nash and Harden as facilitators, since everyone else will want to stretch the floor.
But with Dwight and Gasol trying to post up, and us not having consistent three-point shooters on the floor, we're featuring the post play...not Nash's penetrations.
Nash hasn't been Nash most of the season. We don't need to put the ball in his hands now, and think that magically, he's going to do the right thing.
Kind of irrelevant anyway, because it sounds like he's going to be out until October.