A good insight into Dumbledore's character that doesn't fall into the trap of casting him as evil. I loved you exposition on the spy game that Voldemort and Dumbledore are playing. I can see Voldemort laughing at this game, I really can.
"What made Draco and Snivellus so important that he would give them every possible chance to change sides when the lives of those who had already chosen the Light side meant so little?" Amen to that. It gets worse when Dumbledore is willing to (effectively) sacrifice Amelia Bones, yet is unwilling to kill a few Death Eaters.
"Because you are hoping that someday, some wonderful day far into the future, Snivellus may accidentally overhear something truly valuable. Some small tidbit that will give you the answer you seek." AND "You are trading lives to buy time, and with that time you hope to solve the great riddle of how to destroy Voldemort."
Unfortunately for Dumbledore, the war of attrition is going worse for the light side than for the dark side. The point of attrition is that you actually have to weaken your enemies. In reality, only the light side is weakening.
In some ways, Dumbledore is a religious fanatic hoping for a miracle that will save them. In this case, Dumbledore is hoping to get saved by the prophesy. He apparently doesn't care about the price that people have to pay for that miracle.