Enies Lobby saving the crew from the Buster call by opening the Gates , reinvigorating ussop's morale, Mr Prince moment when luffy, zoro, ussop, nami,and smokey were imprisoned and hadn't a chance to escape.. saved the crew from BM, Saved momo from being executed (who's death would have donned gloom over the allies and imminent defeat), Saved chopper and stood as an example of courage when hoax news about luffy dying was being spread..
in all of these cases.. not only was he a becon of hope but a source morale and initiative.. that coincides well with the symbolic meaning of a Phoenix