RE: big enough or one more year??
Luckyone, I agree with your decision to let him walk.
I would let him walk, but that is because of where my goals lie. For me to shoot a buck, it has to be a monster. Not everyone I hunt around would let a deer like this go, but I feel like someone's gotta start somewhere. You might try to visit with the other hunters if you get a chance, and make a gentleman's agreement to let younger deer go. You don't have anything to lose, and they probably share the same concerns when letting a deer walk that you do.
Many hunters would probably shoot this deer, using the logic that if they don't shoot him, someone else will. IMHO, the probabilty that someone else will not do their part to manage the resource is in no way an excuse for me to do the same.