In what universe is Jeff Green better than Josh Smith? ...at anything?
Both are really talented players. Playing PF, Josh has the upper hand but (not comparing to Green) is undersized for the position. He, too, defends very well. Playing SF, I would take Green anytime over Josh. Green is quicker and better in offensive skills set.
Now. If I were Danny Ainge, I would make another run for the title by employing Nene and Grant Hill. I will also include the likes of Ajinca, Ben Hansbrough and Gilbert Brown. Going through the season with the Old Big Three and giving them at least 30 minutes of playing time would spell disaster for the team's campaign. Spend big money for Nene even if it means going over luxury tax since there is no more way to bring glory to the Big Three if they remain to be the team's anchor. The Big Three must support any moves of transition like giving more PTs to JG, Bradley, JJJ, Nene (if we acquire him) and accepting supporting roles in most of the games. I would not support a "blow-up-the-team" move as the Big Three could yet be your best supporting cast for a new batch of players led by Rondo. Spend for a real talent like Nene since KG and Ray's contract will be through anyway when the season is over. If there could be success in this scenario, then maybe Dwight might come over here and play alongside Nene, KG (re-signed for a lower salary), JJJ and JO.