I haven't kept up with the entire thread, but I did have an idea for you (unless this has already been said). Does he have a leave it command? If I were you, I'd really work on that for a while before I went on a walk with him again. Make that something that's super important and reward him with something obscenely delicious...then go on a short walk, take the same treats, and see what happens.
Same thing with a "watch me" command. If you have make a really strong "watch me" you shouldn't have a problem with meeting other people or dogs on your walks. As soon as you see someone coming, tell him "watch me" and feed him those special goodies while the people or dogs pass.
Again, sorry if something like this has already been mentioned. 