John Hollinger says the Houston Rockets had the most offseason improvement:
In the big picture, the Rockets aggressively addressed their three main problems: stagant offense, point guard and power forward. Between the coaching change, the additions of James and first-round pick Aaron Brooks at the point, the pickups of Scola and Butler up front, and the de facto addition of Wells, this team suddenly looks loaded. At this point in the offseason, nobody has upgraded more than this club.
I tend to agree. Is it possible that the West now has the four best teams in the league? This sounds like a better lineup than Cleveland or Detroit can muster.