We have a strong-willed, wants to be the pack leader, herding terrier. I would suggest that you do need to another round of training, but it needs to be one-on-one instead of group training. Your dog needs the individual attention. Sounds like he may need some more socialization, too. Do you take him to your local dog park and let him off leash to run around, play with other dogs and come in contact with other humans?
I also would suggest using an empty soda can filled w/ a few coins for deterrence training. This has worked enormously with our dog and undesirable behaviors (chasing our cat, jumping on people, trying to run out the front door when it is opened). Dogs have very keen hearing and the throwing down of the coin-filled can at the moment of bad behavior startles the bejeesuz out of them. For instance, have your husband ring the front door. When your dog starts barking or lunging, immediately throw the can on the ground. Do it a few times when the bad behavior comes out and I think you'll see a world of difference in your dog. We did in ours. I personally would not use the shock collars, I don't know of any trainer that recommends these. Try the can.
As for walking, you need to reign in the leash and use a choke collar. Keep the choke chain high up on his neck right under base of the skull and hold the leash high. Have the loop in one hand and use your other hand to quickly pull and keep him in check right next to you. He should not be lunging ahead of you. YOU are the leader. Bring some stinky, smelly tiny treats with you and have them in your hand and reward good behavior. When we were training our dog and someone was walking by, we made our dog sit and stay while they walked by. If he tried to get back up or lunge, we did a quick yank back to us and forced the sit. Give another smelly treat. Have him sit often during walking and give the treat. Change directions in walking quickly if he's trying to pull ahead. Point is, you lead, you make the moves and he follows. YOU are in charge.
You're not going to change this behavior with easy fixes. But it can be changed. The question is are you willing to put the time (and money) into re-training your dog. If he's your "baby," I think you will. Very best of luck to you!!
ADDED: You're getting suggestions other than SHOCK collars because a lot of people don't agree with that method. I think it's ridiculous to post on a forum and tell people how you want them to respond, don't you?