Nash is still valuable. He's probably the best shooter in the league, and that doesn't require young legs or athleticism to be of value for 25-28 mpg (perhaps off the bench). He may not be able to stop the young PGs on defense, but to be honest, there are less than 10 guys in the league that can stop players like DRose, Westbrook and CP3. Nash is still above average on offense when healthy, and can be an important piece in a championship run.
He wouldnt make the cut on Zen masters team! Phil has already said the lakers need a new point guard meaning Steve Nash will never win anything with the style he plays. He never won anything when at his best, so taking the ball out his hands and making him a jump shooter is whats best but we need a point guard that can do everything. Somebody who can compete, not easily get shut down