The Laker's roster is old and built for a half court set. D'Antoni teaches fast pace and giving up some shots to increase pace on defense. Literally maybe the WORST possible coach you could pick with NBA experience for this team. Jackson was probably the best because of his ability to manage big personalities and half court preference, but Jerry Buss doesn't get along with his sister, Jeannie, and she dates Phil. He couldn't bring himself to let her back in the picture after his father left the team to him.
To answer your question, what they need is wing defense, outside shooting, and vast amounts of youth to help eat the grind of the season in this fast paced offense. I think Nash has proven he can run D'Antonis offense effectively, so since they chose his offense I don't think PG needs upgraded.
I REALLY hope they sneak into the 8th seed because that means the Cavs will steal the pick. If it is in the lottery, the Suns will take it over.