Didn't Dooling's performance in the playoffs show why he is the better choice? He can defend his man and turn him all the way up the court. With the acquisition of Terry, we now have a shooter/scorer off the bench to complement him. Moore struggles to bring the ball up the court against pressure, yet cannot apply any pressure himself lest he be beat off the dribble.
Moore can shoot a bit, but he is too small and too slow to be a quality 2. His playmaking skills are suspect and he forces too much offense with mixed results in the NBA summer league. Most of these guys won't be in the NBA and he has trouble both defending them and handling their ball pressure.
Moore is a fringe NBA player at best. Dooling doesn't playmake or shoot particularly well, although he can get hot sometimes, but he is a proven NBA-quality in your shirt defender who is quick enough to stay with point guards and make life difficult for them. He and Terry are the perfect complement off the bench.
People just insist on being infatuated with "developing young guys" no matter what their skill level. Moore's quickness and lack of height are not going to be "developed", he is not a future starter in the league. Dooling is a vet who knows he is a backup and knows what to do in the limited time he is in the game. Not even close who should be the backup to Rondo.