I think you should DEFINATELY neuter this dog. I think you are going to see a lot of changes in your dog that will make him more favorable!
I have 2 boys, one is neutered and one is not. The one that is, is calmer, does not sniff other dogs, is housebroken and more laid back. The one that is not altered has some similar problems as your dog does. He sniffs other dogs privates all the time, hes very high strung also. I know getting him fixed will help him as well as me!